diff options
Diffstat (limited to 'proto/bgp/attrs.c')
| -rw-r--r-- | proto/bgp/attrs.c | 2765 |
1 files changed, 1399 insertions, 1366 deletions
diff --git a/proto/bgp/attrs.c b/proto/bgp/attrs.c index 73eb4040..0f41f818 100644 --- a/proto/bgp/attrs.c +++ b/proto/bgp/attrs.c @@ -2,6 +2,8 @@ * BIRD -- BGP Attributes * * (c) 2000 Martin Mares <mj@ucw.cz> + * (c) 2008--2016 Ondrej Zajicek <santiago@crfreenet.org> + * (c) 2008--2016 CZ.NIC z.s.p.o. * * Can be freely distributed and used under the terms of the GNU GPL. */ @@ -39,888 +41,1266 @@ * specifies that such updates should be ignored, but that is generally * a bad idea. * - * Error checking of optional transitive attributes is done according to - * draft-ietf-idr-optional-transitive-03, but errors are handled always - * as withdraws. + * BGP attribute table has several hooks: * - * Unexpected AS_CONFED_* segments in AS_PATH are logged and removed, - * but unknown segments cause a session drop with Malformed AS_PATH - * error (see validate_path()). The behavior in such case is not - * explicitly specified by RFC 4271. RFC 5065 specifies that - * inconsistent AS_CONFED_* segments should cause a session drop, but - * implementations that pass invalid AS_CONFED_* segments are - * widespread. + * export - Hook that validates and normalizes attribute during export phase. + * Receives eattr, may modify it (e.g., sort community lists for canonical + * representation), UNSET() it (e.g., skip empty lists), or WITHDRAW() it if + * necessary. May assume that eattr has value valid w.r.t. its type, but may be + * invalid w.r.t. BGP constraints. Optional. * - * Error handling of AS4_* attributes is done as specified by RFC 6793. There - * are several possible inconsistencies between AGGREGATOR and AS4_AGGREGATOR - * that are not handled by that RFC, these are logged and ignored (see - * bgp_reconstruct_4b_attrs()). + * encode - Hook that converts internal representation to external one during + * packet writing. Receives eattr and puts it in the buffer (including attribute + * header). Returns number of bytes, or -1 if not enough space. May assume that + * eattr has value valid w.r.t. its type and validated by export hook. Mandatory + * for all known attributes that exist internally after export phase (i.e., all + * except pseudoattributes MP_(UN)REACH_NLRI). + * + * decode - Hook that converts external representation to internal one during + * packet parsing. Receives attribute data in buffer, validates it and adds + * attribute to ea_list. If data are invalid, steps DISCARD(), WITHDRAW() or + * bgp_parse_error() may be used to escape. Mandatory for all known attributes. + * + * format - Optional hook that converts eattr to textual representation. */ -static byte bgp_mandatory_attrs[] = { BA_ORIGIN, BA_AS_PATH -#ifndef IPV6 -,BA_NEXT_HOP -#endif +struct bgp_attr_desc { + const char *name; + uint type; + uint flags; + void (*export)(struct bgp_export_state *s, eattr *a); + int (*encode)(struct bgp_write_state *s, eattr *a, byte *buf, uint size); + void (*decode)(struct bgp_parse_state *s, uint code, uint flags, byte *data, uint len, ea_list **to); + void (*format)(eattr *ea, byte *buf, uint size); }; -struct attr_desc { - char *name; - int expected_length; - int expected_flags; - int type; - int allow_in_ebgp; - int (*validate)(struct bgp_proto *p, byte *attr, int len); - void (*format)(eattr *ea, byte *buf, int buflen); -}; +static const struct bgp_attr_desc bgp_attr_table[]; + +static inline int bgp_attr_known(uint code); + +eattr * +bgp_set_attr(ea_list **attrs, struct linpool *pool, uint code, uint flags, uintptr_t val) +{ + ASSERT(bgp_attr_known(code)); + + ea_list *a = lp_alloc(pool, sizeof(ea_list) + sizeof(eattr)); + eattr *e = &a->attrs[0]; + + a->flags = EALF_SORTED; + a->count = 1; + a->next = *attrs; + *attrs = a; + + e->id = EA_CODE(EAP_BGP, code); + e->type = bgp_attr_table[code].type; + e->flags = flags; + + if (e->type & EAF_EMBEDDED) + e->u.data = (u32) val; + else + e->u.ptr = (struct adata *) val; + + return e; +} + + + +#define REPORT(msg, args...) \ + ({ log(L_REMOTE "%s: " msg, s->proto->p.name, ## args); }) + +#define DISCARD(msg, args...) \ + ({ REPORT(msg, ## args); return; }) -#define IGNORE -1 -#define WITHDRAW -2 +#define WITHDRAW(msg, args...) \ + ({ REPORT(msg, ## args); s->err_withdraw = 1; return; }) + +#define UNSET(a) \ + ({ a->type = EAF_TYPE_UNDEF; return; }) + +#define NEW_BGP "Discarding %s attribute received from AS4-aware neighbor" +#define BAD_EBGP "Discarding %s attribute received from EBGP neighbor" +#define BAD_LENGTH "Malformed %s attribute - invalid length (%u)" +#define BAD_VALUE "Malformed %s attribute - invalid value (%u)" +#define NO_MANDATORY "Missing mandatory %s attribute" + + +static inline int +bgp_put_attr_hdr3(byte *buf, uint code, uint flags, uint len) +{ + *buf++ = flags; + *buf++ = code; + *buf++ = len; + return 3; +} + +static inline int +bgp_put_attr_hdr4(byte *buf, uint code, uint flags, uint len) +{ + *buf++ = flags | BAF_EXT_LEN; + *buf++ = code; + put_u16(buf, len); + return 4; +} + +static inline int +bgp_put_attr_hdr(byte *buf, uint code, uint flags, uint len) +{ + if (len < 256) + return bgp_put_attr_hdr3(buf, code, flags, len); + else + return bgp_put_attr_hdr4(buf, code, flags, len); +} static int -bgp_check_origin(struct bgp_proto *p UNUSED, byte *a, int len UNUSED) +bgp_encode_u8(struct bgp_write_state *s UNUSED, eattr *a, byte *buf, uint size) { - if (*a > 2) - return 6; - return 0; + if (size < (3+1)) + return -1; + + bgp_put_attr_hdr3(buf, EA_ID(a->id), a->flags, 1); + buf[3] = a->u.data; + + return 3+1; } -static void -bgp_format_origin(eattr *a, byte *buf, int buflen UNUSED) +static int +bgp_encode_u32(struct bgp_write_state *s UNUSED, eattr *a, byte *buf, uint size) { - static char *bgp_origin_names[] = { "IGP", "EGP", "Incomplete" }; + if (size < (3+4)) + return -1; - bsprintf(buf, bgp_origin_names[a->u.data]); + bgp_put_attr_hdr3(buf, EA_ID(a->id), a->flags, 4); + put_u32(buf+3, a->u.data); + + return 3+4; } static int -path_segment_contains(byte *p, int bs, u32 asn) +bgp_encode_u32s(struct bgp_write_state *s UNUSED, eattr *a, byte *buf, uint size) { - int i; - int len = p[1]; - p += 2; + uint len = a->u.ptr->length; - for(i=0; i<len; i++) - { - u32 asn2 = (bs == 4) ? get_u32(p) : get_u16(p); - if (asn2 == asn) - return 1; - p += bs; - } + if (size < (4+len)) + return -1; - return 0; + uint hdr = bgp_put_attr_hdr(buf, EA_ID(a->id), a->flags, len); + put_u32s(buf + hdr, (u32 *) a->u.ptr->data, len / 4); + + return hdr + len; } -/* Validates path attribute, removes AS_CONFED_* segments, and also returns path length */ static int -validate_path(struct bgp_proto *p, int as_path, int bs, byte *idata, uint *ilength) +bgp_put_attr(byte *buf, uint size, uint code, uint flags, byte *data, uint len) { - int res = 0; - u8 *a, *dst; - int len, plen; + if (size < (4+len)) + return -1; - dst = a = idata; - len = *ilength; + uint hdr = bgp_put_attr_hdr(buf, code, flags, len); + memcpy(buf + hdr, data, len); - while (len) - { - if (len < 2) - return -1; - - plen = 2 + bs * a[1]; - if (len < plen) - return -1; - - if (a[1] == 0) - { - log(L_WARN "%s: %s_PATH attribute contains empty segment, skipping it", - p->p.name, as_path ? "AS" : "AS4"); - goto skip; - } - - switch (a[0]) - { - case AS_PATH_SET: - res++; - break; - - case AS_PATH_SEQUENCE: - res += a[1]; - break; - - case AS_PATH_CONFED_SEQUENCE: - case AS_PATH_CONFED_SET: - if (as_path && path_segment_contains(a, bs, p->remote_as)) - { - log(L_WARN "%s: AS_CONFED_* segment with peer ASN found, misconfigured confederation?", p->p.name); - return -1; - } - - log(L_WARN "%s: %s_PATH attribute contains AS_CONFED_* segment, skipping segment", - p->p.name, as_path ? "AS" : "AS4"); - goto skip; - - default: - return -1; - } - - if (dst != a) - memmove(dst, a, plen); - dst += plen; - - skip: - len -= plen; - a += plen; - } + return hdr + len; +} - *ilength = dst - idata; - return res; +static int +bgp_encode_raw(struct bgp_write_state *s UNUSED, eattr *a, byte *buf, uint size) +{ + return bgp_put_attr(buf, size, EA_ID(a->id), a->flags, a->u.ptr->data, a->u.ptr->length); } -static inline int -validate_as_path(struct bgp_proto *p, byte *a, int *len) + +/* + * Attribute hooks + */ + +static void +bgp_export_origin(struct bgp_export_state *s, eattr *a) { - return validate_path(p, 1, p->as4_session ? 4 : 2, a, len); + if (a->u.data > 2) + WITHDRAW(BAD_VALUE, "ORIGIN", a->u.data); } -static inline int -validate_as4_path(struct bgp_proto *p, struct adata *path) +static void +bgp_decode_origin(struct bgp_parse_state *s, uint code UNUSED, uint flags, byte *data, uint len, ea_list **to) +{ + if (len != 1) + WITHDRAW(BAD_LENGTH, "ORIGIN", len); + + if (data[0] > 2) + WITHDRAW(BAD_VALUE, "ORIGIN", data[0]); + + bgp_set_attr_u32(to, s->pool, BA_ORIGIN, flags, data[0]); +} + +static void +bgp_format_origin(eattr *a, byte *buf, uint size UNUSED) +{ + static const char *bgp_origin_names[] = { "IGP", "EGP", "Incomplete" }; + + bsprintf(buf, (a->u.data <= 2) ? bgp_origin_names[a->u.data] : "?"); +} + + +static int +bgp_encode_as_path(struct bgp_write_state *s, eattr *a, byte *buf, uint size) +{ + byte *data = a->u.ptr->data; + uint len = a->u.ptr->length; + + if (!s->as4_session) + { + /* Prepare 16-bit AS_PATH (from 32-bit one) in a temporary buffer */ + byte *src = data; + data = alloca(len); + len = as_path_32to16(data, src, len); + } + + return bgp_put_attr(buf, size, BA_AS_PATH, a->flags, data, len); +} + +static void +bgp_decode_as_path(struct bgp_parse_state *s, uint code UNUSED, uint flags, byte *data, uint len, ea_list **to) { - return validate_path(p, 0, 4, path->data, &path->length); + struct bgp_proto *p = s->proto; + int as_length = s->as4_session ? 4 : 2; + int as_confed = p->cf->confederation && p->is_interior; + char err[128]; + + if (!as_path_valid(data, len, as_length, as_confed, err, sizeof(err))) + WITHDRAW("Malformed AS_PATH attribute - %s", err); + + /* In some circumstances check for initial AS_CONFED_SEQUENCE; RFC 5065 5.0 */ + if (p->is_interior && !p->is_internal && + ((len < 2) || (data[0] != AS_PATH_CONFED_SEQUENCE))) + WITHDRAW("Malformed AS_PATH attribute - %s", "missing initial AS_CONFED_SEQUENCE"); + + if (!s->as4_session) + { + /* Prepare 32-bit AS_PATH (from 16-bit one) in a temporary buffer */ + byte *src = data; + data = alloca(2*len); + len = as_path_16to32(data, src, len); + } + + bgp_set_attr_data(to, s->pool, BA_AS_PATH, flags, data, len); } + static int -bgp_check_next_hop(struct bgp_proto *p UNUSED, byte *a UNUSED6, int len UNUSED6) +bgp_encode_next_hop(struct bgp_write_state *s, eattr *a, byte *buf, uint size) { -#ifdef IPV6 - return IGNORE; -#else - ip_addr addr; + /* + * The NEXT_HOP attribute is used only in traditional (IPv4) BGP. In MP-BGP, + * the next hop is encoded as a part of the MP_REACH_NLRI attribute, so we + * store it and encode it later by AFI-specific hooks. + */ + + if (s->channel->afi == BGP_AF_IPV4) + { + ASSERT(a->u.ptr->length == sizeof(ip_addr)); - memcpy(&addr, a, len); - ipa_ntoh(addr); - if (ipa_classify(addr) & IADDR_HOST) + if (size < (3+4)) + return -1; + + bgp_put_attr_hdr3(buf, BA_NEXT_HOP, a->flags, 4); + put_ip4(buf+3, ipa_to_ip4( *(ip_addr *) a->u.ptr->data )); + + return 3+4; + } + else + { + s->mp_next_hop = a; return 0; + } +} + +static void +bgp_decode_next_hop(struct bgp_parse_state *s, uint code UNUSED, uint flags UNUSED, byte *data, uint len, ea_list **to UNUSED) +{ + if (len != 4) + WITHDRAW(BAD_LENGTH, "NEXT_HOP", len); + + /* Semantic checks are done later */ + s->ip_next_hop_len = len; + s->ip_next_hop_data = data; +} + +/* TODO: This function should use AF-specific hook */ +static void +bgp_format_next_hop(eattr *a, byte *buf, uint size UNUSED) +{ + ip_addr *nh = (void *) a->u.ptr->data; + uint len = a->u.ptr->length; + + ASSERT((len == 16) || (len == 32)); + + /* in IPv6, we may have two addresses in NEXT HOP */ + if ((len == 16) || ipa_zero(nh[1])) + bsprintf(buf, "%I", nh[0]); else - return 8; -#endif + bsprintf(buf, "%I %I", nh[0], nh[1]); } + static void -bgp_format_next_hop(eattr *a, byte *buf, int buflen UNUSED) +bgp_decode_med(struct bgp_parse_state *s, uint code UNUSED, uint flags, byte *data, uint len, ea_list **to) { - ip_addr *ipp = (ip_addr *) a->u.ptr->data; -#ifdef IPV6 - /* in IPv6, we might have two addresses in NEXT HOP */ - if ((a->u.ptr->length == NEXT_HOP_LENGTH) && ipa_nonzero(ipp[1])) - { - bsprintf(buf, "%I %I", ipp[0], ipp[1]); - return; - } -#endif + if (len != 4) + WITHDRAW(BAD_LENGTH, "MULTI_EXIT_DISC", len); - bsprintf(buf, "%I", ipp[0]); + u32 val = get_u32(data); + bgp_set_attr_u32(to, s->pool, BA_MULTI_EXIT_DISC, flags, val); } -static int -bgp_check_aggregator(struct bgp_proto *p, byte *a UNUSED, int len) + +static void +bgp_export_local_pref(struct bgp_export_state *s, eattr *a) { - int exp_len = p->as4_session ? 8 : 6; - - return (len == exp_len) ? 0 : WITHDRAW; + if (!s->proto->is_interior && !s->proto->cf->allow_local_pref) + UNSET(a); } static void -bgp_format_aggregator(eattr *a, byte *buf, int buflen UNUSED) +bgp_decode_local_pref(struct bgp_parse_state *s, uint code UNUSED, uint flags, byte *data, uint len, ea_list **to) { - struct adata *ad = a->u.ptr; - byte *data = ad->data; - u32 as; + if (!s->proto->is_interior && !s->proto->cf->allow_local_pref) + DISCARD(BAD_EBGP, "LOCAL_PREF"); - as = get_u32(data); - data += 4; + if (len != 4) + WITHDRAW(BAD_LENGTH, "LOCAL_PREF", len); - bsprintf(buf, "%d.%d.%d.%d AS%u", data[0], data[1], data[2], data[3], as); + u32 val = get_u32(data); + bgp_set_attr_u32(to, s->pool, BA_LOCAL_PREF, flags, val); } -static int -bgp_check_community(struct bgp_proto *p UNUSED, byte *a UNUSED, int len) + +static void +bgp_decode_atomic_aggr(struct bgp_parse_state *s, uint code UNUSED, uint flags, byte *data UNUSED, uint len, ea_list **to) { - return ((len % 4) == 0) ? 0 : WITHDRAW; + if (len != 0) + DISCARD(BAD_LENGTH, "ATOMIC_AGGR", len); + + bgp_set_attr_data(to, s->pool, BA_ATOMIC_AGGR, flags, NULL, 0); } static int -bgp_check_cluster_list(struct bgp_proto *p UNUSED, byte *a UNUSED, int len) +bgp_encode_aggregator(struct bgp_write_state *s, eattr *a, byte *buf, uint size) { - return ((len % 4) == 0) ? 0 : 5; + byte *data = a->u.ptr->data; + uint len = a->u.ptr->length; + + if (!s->as4_session) + { + /* Prepare 16-bit AGGREGATOR (from 32-bit one) in a temporary buffer */ + byte *src = data; + data = alloca(6); + len = aggregator_32to16(data, src); + } + + return bgp_put_attr(buf, size, BA_AGGREGATOR, a->flags, data, len); } static void -bgp_format_cluster_list(eattr *a, byte *buf, int buflen) +bgp_decode_aggregator(struct bgp_parse_state *s, uint code UNUSED, uint flags, byte *data, uint len, ea_list **to) { - /* Truncates cluster lists larger than buflen, probably not a problem */ - int_set_format(a->u.ptr, 0, -1, buf, buflen); + if (len != (s->as4_session ? 8 : 6)) + DISCARD(BAD_LENGTH, "AGGREGATOR", len); + + if (!s->as4_session) + { + /* Prepare 32-bit AGGREGATOR (from 16-bit one) in a temporary buffer */ + byte *src = data; + data = alloca(8); + len = aggregator_16to32(data, src); + } + + bgp_set_attr_data(to, s->pool, BA_AGGREGATOR, flags, data, len); } -static int -bgp_check_reach_nlri(struct bgp_proto *p UNUSED, byte *a UNUSED, int len UNUSED) +static void +bgp_format_aggregator(eattr *a, byte *buf, uint size UNUSED) { -#ifdef IPV6 - p->mp_reach_start = a; - p->mp_reach_len = len; -#endif - return IGNORE; + byte *data = a->u.ptr->data; + + bsprintf(buf, "%I4 AS%u", get_ip4(data+4), get_u32(data+0)); } -static int -bgp_check_unreach_nlri(struct bgp_proto *p UNUSED, byte *a UNUSED, int len UNUSED) + +static void +bgp_export_community(struct bgp_export_state *s, eattr *a) { -#ifdef IPV6 - p->mp_unreach_start = a; - p->mp_unreach_len = len; -#endif - return IGNORE; + if (a->u.ptr->length == 0) + UNSET(a); + + a->u.ptr = int_set_sort(s->pool, a->u.ptr); } -static int -bgp_check_ext_community(struct bgp_proto *p UNUSED, byte *a UNUSED, int len) +static void +bgp_decode_community(struct bgp_parse_state *s, uint code UNUSED, uint flags, byte *data, uint len, ea_list **to) { - return ((len % 8) == 0) ? 0 : WITHDRAW; + if (!len || (len % 4)) + WITHDRAW(BAD_LENGTH, "COMMUNITY", len); + + struct adata *ad = lp_alloc_adata(s->pool, len); + get_u32s(data, (u32 *) ad->data, len / 4); + bgp_set_attr_ptr(to, s->pool, BA_COMMUNITY, flags, ad); } -static int -bgp_check_large_community(struct bgp_proto *p UNUSED, byte *a UNUSED, int len) -{ - return ((len % 12) == 0) ? 0 : WITHDRAW; -} - - -static struct attr_desc bgp_attr_table[] = { - { NULL, -1, 0, 0, 0, /* Undefined */ - NULL, NULL }, - { "origin", 1, BAF_TRANSITIVE, EAF_TYPE_INT, 1, /* BA_ORIGIN */ - bgp_check_origin, bgp_format_origin }, - { "as_path", -1, BAF_TRANSITIVE, EAF_TYPE_AS_PATH, 1, /* BA_AS_PATH */ - NULL, NULL }, /* is checked by validate_as_path() as a special case */ - { "next_hop", 4, BAF_TRANSITIVE, EAF_TYPE_IP_ADDRESS, 1, /* BA_NEXT_HOP */ - bgp_check_next_hop, bgp_format_next_hop }, - { "med", 4, BAF_OPTIONAL, EAF_TYPE_INT, 1, /* BA_MULTI_EXIT_DISC */ - NULL, NULL }, - { "local_pref", 4, BAF_TRANSITIVE, EAF_TYPE_INT, 1, /* BA_LOCAL_PREF */ - NULL, NULL }, - { "atomic_aggr", 0, BAF_TRANSITIVE, EAF_TYPE_OPAQUE, 1, /* BA_ATOMIC_AGGR */ - NULL, NULL }, - { "aggregator", -1, BAF_OPTIONAL | BAF_TRANSITIVE, EAF_TYPE_OPAQUE, 1, /* BA_AGGREGATOR */ - bgp_check_aggregator, bgp_format_aggregator }, - { "community", -1, BAF_OPTIONAL | BAF_TRANSITIVE, EAF_TYPE_INT_SET, 1, /* BA_COMMUNITY */ - bgp_check_community, NULL }, - { "originator_id", 4, BAF_OPTIONAL, EAF_TYPE_ROUTER_ID, 0, /* BA_ORIGINATOR_ID */ - NULL, NULL }, - { "cluster_list", -1, BAF_OPTIONAL, EAF_TYPE_INT_SET, 0, /* BA_CLUSTER_LIST */ - bgp_check_cluster_list, bgp_format_cluster_list }, - { .name = NULL }, /* BA_DPA */ - { .name = NULL }, /* BA_ADVERTISER */ - { .name = NULL }, /* BA_RCID_PATH */ - { "mp_reach_nlri", -1, BAF_OPTIONAL, EAF_TYPE_OPAQUE, 1, /* BA_MP_REACH_NLRI */ - bgp_check_reach_nlri, NULL }, - { "mp_unreach_nlri", -1, BAF_OPTIONAL, EAF_TYPE_OPAQUE, 1, /* BA_MP_UNREACH_NLRI */ - bgp_check_unreach_nlri, NULL }, - { "ext_community", -1, BAF_OPTIONAL | BAF_TRANSITIVE, EAF_TYPE_EC_SET, 1, /* BA_EXT_COMMUNITY */ - bgp_check_ext_community, NULL }, - { "as4_path", -1, BAF_OPTIONAL | BAF_TRANSITIVE, EAF_TYPE_OPAQUE, 1, /* BA_AS4_PATH */ - NULL, NULL }, - { "as4_aggregator", -1, BAF_OPTIONAL | BAF_TRANSITIVE, EAF_TYPE_OPAQUE, 1, /* BA_AS4_PATH */ - NULL, NULL }, - [BA_LARGE_COMMUNITY] = - { "large_community", -1, BAF_OPTIONAL | BAF_TRANSITIVE, EAF_TYPE_LC_SET, 1, - bgp_check_large_community, NULL } -}; -/* BA_AS4_PATH is type EAF_TYPE_OPAQUE and not type EAF_TYPE_AS_PATH. - * It does not matter as this attribute does not appear on routes in the routing table. - */ +static void +bgp_export_originator_id(struct bgp_export_state *s, eattr *a) +{ + if (!s->proto->is_internal) + UNSET(a); +} -#define ATTR_KNOWN(code) ((code) < ARRAY_SIZE(bgp_attr_table) && bgp_attr_table[code].name) +static void +bgp_decode_originator_id(struct bgp_parse_state *s, uint code UNUSED, uint flags, byte *data, uint len, ea_list **to) +{ + if (!s->proto->is_internal) + DISCARD(BAD_EBGP, "ORIGINATOR_ID"); -static inline struct adata * -bgp_alloc_adata(struct linpool *pool, unsigned len) + if (len != 4) + WITHDRAW(BAD_LENGTH, "ORIGINATOR_ID", len); + + u32 val = get_u32(data); + bgp_set_attr_u32(to, s->pool, BA_ORIGINATOR_ID, flags, val); +} + + +static void +bgp_export_cluster_list(struct bgp_export_state *s UNUSED, eattr *a) { - struct adata *ad = lp_alloc(pool, sizeof(struct adata) + len); - ad->length = len; - return ad; + if (!s->proto->is_internal) + UNSET(a); + + if (a->u.ptr->length == 0) + UNSET(a); } static void -bgp_set_attr(eattr *e, unsigned attr, uintptr_t val) +bgp_decode_cluster_list(struct bgp_parse_state *s, uint code UNUSED, uint flags, byte *data, uint len, ea_list **to) { - ASSERT(ATTR_KNOWN(attr)); - e->id = EA_CODE(EAP_BGP, attr); - e->type = bgp_attr_table[attr].type; - e->flags = bgp_attr_table[attr].expected_flags; - if (e->type & EAF_EMBEDDED) - e->u.data = val; - else - e->u.ptr = (struct adata *) val; + if (!s->proto->is_internal) + DISCARD(BAD_EBGP, "CLUSTER_LIST"); + + if (!len || (len % 4)) + WITHDRAW(BAD_LENGTH, "CLUSTER_LIST", len); + + struct adata *ad = lp_alloc_adata(s->pool, len); + get_u32s(data, (u32 *) ad->data, len / 4); + bgp_set_attr_ptr(to, s->pool, BA_CLUSTER_LIST, flags, ad); } -static byte * -bgp_set_attr_wa(eattr *e, struct linpool *pool, unsigned attr, unsigned len) +static void +bgp_format_cluster_list(eattr *a, byte *buf, uint size) { - struct adata *ad = bgp_alloc_adata(pool, len); - bgp_set_attr(e, attr, (uintptr_t) ad); - return ad->data; + /* Truncates cluster lists larger than buflen, probably not a problem */ + int_set_format(a->u.ptr, 0, -1, buf, size); } -void -bgp_attach_attr(ea_list **to, struct linpool *pool, unsigned attr, uintptr_t val) + +static inline u32 +get_af3(byte *buf) { - ea_list *a = lp_alloc(pool, sizeof(ea_list) + sizeof(eattr)); - a->next = *to; - *to = a; - a->flags = EALF_SORTED; - a->count = 1; - bgp_set_attr(a->attrs, attr, val); + return (get_u16(buf) << 16) | buf[2]; } -byte * -bgp_attach_attr_wa(ea_list **to, struct linpool *pool, unsigned attr, unsigned len) +static void +bgp_decode_mp_reach_nlri(struct bgp_parse_state *s, uint code UNUSED, uint flags UNUSED, byte *data, uint len, ea_list **to UNUSED) { - struct adata *ad = bgp_alloc_adata(pool, len); - bgp_attach_attr(to, pool, attr, (uintptr_t) ad); - return ad->data; + /* + * 2 B MP_REACH_NLRI data - Address Family Identifier + * 1 B MP_REACH_NLRI data - Subsequent Address Family Identifier + * 1 B MP_REACH_NLRI data - Length of Next Hop Network Address + * var MP_REACH_NLRI data - Network Address of Next Hop + * 1 B MP_REACH_NLRI data - Reserved (zero) + * var MP_REACH_NLRI data - Network Layer Reachability Information + */ + + if ((len < 5) || (len < (5 + (uint) data[3]))) + bgp_parse_error(s, 9); + + s->mp_reach_af = get_af3(data); + s->mp_next_hop_len = data[3]; + s->mp_next_hop_data = data + 4; + s->mp_reach_len = len - 5 - s->mp_next_hop_len; + s->mp_reach_nlri = data + 5 + s->mp_next_hop_len; } -static int -bgp_encode_attr_hdr(byte *dst, uint flags, unsigned code, int len) + +static void +bgp_decode_mp_unreach_nlri(struct bgp_parse_state *s, uint code UNUSED, uint flags UNUSED, byte *data, uint len, ea_list **to UNUSED) { - int wlen; + /* + * 2 B MP_UNREACH_NLRI data - Address Family Identifier + * 1 B MP_UNREACH_NLRI data - Subsequent Address Family Identifier + * var MP_UNREACH_NLRI data - Network Layer Reachability Information + */ - DBG("\tAttribute %02x (%d bytes, flags %02x)\n", code, len, flags); + if (len < 3) + bgp_parse_error(s, 9); + + s->mp_unreach_af = get_af3(data); + s->mp_unreach_len = len - 3; + s->mp_unreach_nlri = data + 3; +} - if (len < 256) - { - *dst++ = flags; - *dst++ = code; - *dst++ = len; - wlen = 3; - } - else - { - *dst++ = flags | BAF_EXT_LEN; - *dst++ = code; - put_u16(dst, len); - wlen = 4; - } - return wlen; +static void +bgp_export_ext_community(struct bgp_export_state *s, eattr *a) +{ + a->u.ptr = ec_set_del_nontrans(s->pool, a->u.ptr); + + if (a->u.ptr->length == 0) + UNSET(a); + + ec_set_sort_x(a->u.ptr); } static void -aggregator_convert_to_old(struct adata *aggr, byte *dst, int *new_used) +bgp_decode_ext_community(struct bgp_parse_state *s, uint code UNUSED, uint flags, byte *data, uint len, ea_list **to) { - byte *src = aggr->data; - *new_used = 0; + if (!len || (len % 8)) + WITHDRAW(BAD_LENGTH, "EXT_COMMUNITY", len); - u32 as = get_u32(src); - if (as > 0xFFFF) - { - as = AS_TRANS; - *new_used = 1; - } - put_u16(dst, as); + struct adata *ad = lp_alloc_adata(s->pool, len); + get_u32s(data, (u32 *) ad->data, len / 4); + bgp_set_attr_ptr(to, s->pool, BA_EXT_COMMUNITY, flags, ad); +} + + +static void +bgp_decode_as4_aggregator(struct bgp_parse_state *s, uint code UNUSED, uint flags, byte *data, uint len, ea_list **to) +{ + if (s->as4_session) + DISCARD(NEW_BGP, "AS4_AGGREGATOR"); - /* Copy IPv4 address */ - memcpy(dst + 2, src + 4, 4); + if (len != 8) + DISCARD(BAD_LENGTH, "AS4_AGGREGATOR", len); + + bgp_set_attr_data(to, s->pool, BA_AS4_AGGREGATOR, flags, data, len); } static void -aggregator_convert_to_new(struct adata *aggr, byte *dst) +bgp_decode_as4_path(struct bgp_parse_state *s, uint code UNUSED, uint flags, byte *data, uint len, ea_list **to) { - byte *src = aggr->data; + char err[128]; + + if (s->as4_session) + DISCARD(NEW_BGP, "AS4_PATH"); + + if (len < 6) + DISCARD(BAD_LENGTH, "AS4_PATH", len); + + if (!as_path_valid(data, len, 4, 1, err, sizeof(err))) + DISCARD("Malformed AS4_PATH attribute - %s", err); + + struct adata *a = lp_alloc_adata(s->pool, len); + memcpy(a->data, data, len); - u32 as = get_u16(src); - put_u32(dst, as); + /* AS_CONFED* segments are invalid in AS4_PATH; RFC 6793 6 */ + if (as_path_contains_confed(a)) + { + REPORT("Discarding AS_CONFED* segment from AS4_PATH attribute"); + a = as_path_strip_confed(s->pool, a); + } - /* Copy IPv4 address */ - memcpy(dst + 4, src + 2, 4); + bgp_set_attr_ptr(to, s->pool, BA_AS4_PATH, flags, a); +} + +static void +bgp_export_large_community(struct bgp_export_state *s, eattr *a) +{ + if (a->u.ptr->length == 0) + UNSET(a); + + a->u.ptr = lc_set_sort(s->pool, a->u.ptr); +} + +static void +bgp_decode_large_community(struct bgp_parse_state *s, uint code UNUSED, uint flags, byte *data, uint len, ea_list **to) +{ + if (!len || (len % 12)) + WITHDRAW(BAD_LENGTH, "LARGE_COMMUNITY", len); + + struct adata *ad = lp_alloc_adata(s->pool, len); + get_u32s(data, (u32 *) ad->data, len / 4); + bgp_set_attr_ptr(to, s->pool, BA_LARGE_COMMUNITY, flags, ad); +} + +static void +bgp_export_mpls_label_stack(struct bgp_export_state *s, eattr *a) +{ + net_addr *n = s->route->net->n.addr; + u32 *labels = (u32 *) a->u.ptr->data; + uint lnum = a->u.ptr->length / 4; + + /* Perhaps we should just ignore it? */ + if (!s->mpls) + WITHDRAW("Unexpected MPLS stack"); + + /* Empty MPLS stack is not allowed */ + if (!lnum) + WITHDRAW("Malformed MPLS stack - empty"); + + /* This is ugly, but we must ensure that labels fit into NLRI field */ + if ((24*lnum + (net_is_vpn(n) ? 64 : 0) + net_pxlen(n)) > 255) + WITHDRAW("Malformed MPLS stack - too many labels (%u)", lnum); + + for (uint i = 0; i < lnum; i++) + { + if (labels[i] > 0xfffff) + WITHDRAW("Malformed MPLS stack - invalid label (%u)", labels[i]); + + /* TODO: Check for special-purpose label values? */ + } } static int -bgp_get_attr_len(eattr *a) +bgp_encode_mpls_label_stack(struct bgp_write_state *s, eattr *a, byte *buf UNUSED, uint size UNUSED) { - int len; - if (ATTR_KNOWN(EA_ID(a->id))) + /* + * MPLS labels are encoded as a part of the NLRI in MP_REACH_NLRI attribute, + * so we store MPLS_LABEL_STACK and encode it later by AFI-specific hooks. + */ + + s->mpls_labels = a->u.ptr; + return 0; +} + +static void +bgp_decode_mpls_label_stack(struct bgp_parse_state *s, uint code UNUSED, uint flags UNUSED, byte *data UNUSED, uint len UNUSED, ea_list **to UNUSED) +{ + DISCARD("Discarding received attribute #0"); +} + +static void +bgp_format_mpls_label_stack(eattr *a, byte *buf, uint size) +{ + u32 *labels = (u32 *) a->u.ptr->data; + uint lnum = a->u.ptr->length / 4; + char *pos = buf; + + for (uint i = 0; i < lnum; i++) + { + if (size < 20) { - int code = EA_ID(a->id); - struct attr_desc *desc = &bgp_attr_table[code]; - len = desc->expected_length; - if (len < 0) - { - ASSERT(!(a->type & EAF_EMBEDDED)); - len = a->u.ptr->length; - } + bsprintf(pos, "..."); + return; } + + uint l = bsprintf(pos, "%d/", labels[i]); + ADVANCE(pos, size, l); + } + + /* Clear last slash or terminate empty string */ + pos[lnum ? -1 : 0] = 0; +} + +static inline void +bgp_decode_unknown(struct bgp_parse_state *s, uint code, uint flags, byte *data, uint len, ea_list **to) +{ + /* Cannot use bgp_set_attr_data() as it works on known attributes only */ + ea_set_attr_data(to, s->pool, EA_CODE(EAP_BGP, code), flags, EAF_TYPE_OPAQUE, data, len); +} + + +/* + * Attribute table + */ + +static const struct bgp_attr_desc bgp_attr_table[] = { + [BA_ORIGIN] = { + .name = "origin", + .type = EAF_TYPE_INT, + .flags = BAF_TRANSITIVE, + .export = bgp_export_origin, + .encode = bgp_encode_u8, + .decode = bgp_decode_origin, + .format = bgp_format_origin, + }, + [BA_AS_PATH] = { + .name = "as_path", + .type = EAF_TYPE_AS_PATH, + .flags = BAF_TRANSITIVE, + .encode = bgp_encode_as_path, + .decode = bgp_decode_as_path, + }, + [BA_NEXT_HOP] = { + .name = "next_hop", + .type = EAF_TYPE_IP_ADDRESS, + .flags = BAF_TRANSITIVE, + .encode = bgp_encode_next_hop, + .decode = bgp_decode_next_hop, + .format = bgp_format_next_hop, + }, + [BA_MULTI_EXIT_DISC] = { + .name = "med", + .type = EAF_TYPE_INT, + .flags = BAF_OPTIONAL, + .encode = bgp_encode_u32, + .decode = bgp_decode_med, + }, + [BA_LOCAL_PREF] = { + .name = "local_pref", + .type = EAF_TYPE_INT, + .flags = BAF_TRANSITIVE, + .export = bgp_export_local_pref, + .encode = bgp_encode_u32, + .decode = bgp_decode_local_pref, + }, + [BA_ATOMIC_AGGR] = { + .name = "atomic_aggr", + .type = EAF_TYPE_OPAQUE, + .flags = BAF_TRANSITIVE, + .encode = bgp_encode_raw, + .decode = bgp_decode_atomic_aggr, + }, + [BA_AGGREGATOR] = { + .name = "aggregator", + .type = EAF_TYPE_OPAQUE, + .flags = BAF_OPTIONAL | BAF_TRANSITIVE, + .encode = bgp_encode_aggregator, + .decode = bgp_decode_aggregator, + .format = bgp_format_aggregator, + }, + [BA_COMMUNITY] = { + .name = "community", + .type = EAF_TYPE_INT_SET, + .flags = BAF_OPTIONAL | BAF_TRANSITIVE, + .export = bgp_export_community, + .encode = bgp_encode_u32s, + .decode = bgp_decode_community, + }, + [BA_ORIGINATOR_ID] = { + .name = "originator_id", + .type = EAF_TYPE_ROUTER_ID, + .flags = BAF_OPTIONAL, + .export = bgp_export_originator_id, + .encode = bgp_encode_u32, + .decode = bgp_decode_originator_id, + }, + [BA_CLUSTER_LIST] = { + .name = "cluster_list", + .type = EAF_TYPE_INT_SET, + .flags = BAF_OPTIONAL, + .export = bgp_export_cluster_list, + .encode = bgp_encode_u32s, + .decode = bgp_decode_cluster_list, + .format = bgp_format_cluster_list, + }, + [BA_MP_REACH_NLRI] = { + .name = "mp_reach_nlri", + .type = EAF_TYPE_OPAQUE, + .flags = BAF_OPTIONAL, + .decode = bgp_decode_mp_reach_nlri, + }, + [BA_MP_UNREACH_NLRI] = { + .name = "mp_unreach_nlri", + .type = EAF_TYPE_OPAQUE, + .flags = BAF_OPTIONAL, + .decode = bgp_decode_mp_unreach_nlri, + }, + [BA_EXT_COMMUNITY] = { + .name = "ext_community", + .type = EAF_TYPE_EC_SET, + .flags = BAF_OPTIONAL | BAF_TRANSITIVE, + .export = bgp_export_ext_community, + .encode = bgp_encode_u32s, + .decode = bgp_decode_ext_community, + }, + [BA_AS4_PATH] = { + .name = "as4_path", + .type = EAF_TYPE_AS_PATH, + .flags = BAF_OPTIONAL | BAF_TRANSITIVE, + .encode = bgp_encode_raw, + .decode = bgp_decode_as4_path, + }, + [BA_AS4_AGGREGATOR] = { + .name = "as4_aggregator", + .type = EAF_TYPE_OPAQUE, + .flags = BAF_OPTIONAL | BAF_TRANSITIVE, + .encode = bgp_encode_raw, + .decode = bgp_decode_as4_aggregator, + .format = bgp_format_aggregator, + }, + [BA_LARGE_COMMUNITY] = { + .name = "large_community", + .type = EAF_TYPE_LC_SET, + .flags = BAF_OPTIONAL | BAF_TRANSITIVE, + .export = bgp_export_large_community, + .encode = bgp_encode_u32s, + .decode = bgp_decode_large_community, + }, + [BA_MPLS_LABEL_STACK] = { + .name = "mpls_label_stack", + .type = EAF_TYPE_INT_SET, + .export = bgp_export_mpls_label_stack, + .encode = bgp_encode_mpls_label_stack, + .decode = bgp_decode_mpls_label_stack, + .format = bgp_format_mpls_label_stack, + }, +}; + +static inline int +bgp_attr_known(uint code) +{ + return (code < ARRAY_SIZE(bgp_attr_table)) && bgp_attr_table[code].name; +} + + +/* + * Attribute export + */ + +static inline void +bgp_export_attr(struct bgp_export_state *s, eattr *a, ea_list *to) +{ + if (EA_PROTO(a->id) != EAP_BGP) + return; + + uint code = EA_ID(a->id); + + if (bgp_attr_known(code)) + { + const struct bgp_attr_desc *desc = &bgp_attr_table[code]; + + /* The flags might have been zero if the attr was added by filters */ + a->flags = (a->flags & BAF_PARTIAL) | desc->flags; + + /* Set partial bit if new opt-trans attribute is attached to non-local route */ + if ((s->src != NULL) && (a->type & EAF_ORIGINATED) && + (a->flags & BAF_OPTIONAL) && (a->flags & BAF_TRANSITIVE)) + a->flags |= BAF_PARTIAL; + + /* Call specific hook */ + CALL(desc->export, s, a); + + /* Attribute might become undefined in hook */ + if ((a->type & EAF_TYPE_MASK) == EAF_TYPE_UNDEF) + return; + } else - { - ASSERT((a->type & EAF_TYPE_MASK) == EAF_TYPE_OPAQUE); - len = a->u.ptr->length; - } - - return len; + { + /* Don't re-export unknown non-transitive attributes */ + if (!(a->flags & BAF_TRANSITIVE)) + return; + + a->flags |= BAF_PARTIAL; + } + + /* Append updated attribute */ + to->attrs[to->count++] = *a; +} + +/** + * bgp_export_attrs - export BGP attributes + * @s: BGP export state + * @attrs: a list of extended attributes + * + * The bgp_export_attrs() function takes a list of attributes and merges it to + * one newly allocated and sorted segment. Attributes are validated and + * normalized by type-specific export hooks and attribute flags are updated. + * Some attributes may be eliminated (e.g. unknown non-tranitive attributes, or + * empty community sets). + * + * Result: one sorted attribute list segment, or NULL if attributes are unsuitable. + */ +static inline ea_list * +bgp_export_attrs(struct bgp_export_state *s, ea_list *attrs) +{ + /* Merge the attribute list */ + ea_list *new = lp_alloc(s->pool, ea_scan(attrs)); + ea_merge(attrs, new); + ea_sort(new); + + uint i, count; + count = new->count; + new->count = 0; + + /* Export each attribute */ + for (i = 0; i < count; i++) + bgp_export_attr(s, &new->attrs[i], new); + + if (s->err_withdraw) + return NULL; + + return new; +} + + +/* + * Attribute encoding + */ + +static inline int +bgp_encode_attr(struct bgp_write_state *s, eattr *a, byte *buf, uint size) +{ + ASSERT(EA_PROTO(a->id) == EAP_BGP); + + uint code = EA_ID(a->id); + + if (bgp_attr_known(code)) + return bgp_attr_table[code].encode(s, a, buf, size); + else + return bgp_encode_raw(s, a, buf, size); } /** * bgp_encode_attrs - encode BGP attributes - * @p: BGP instance - * @w: buffer + * @s: BGP write state * @attrs: a list of extended attributes - * @remains: remaining space in the buffer + * @buf: buffer + * @end: buffer end * * The bgp_encode_attrs() function takes a list of extended attributes * and converts it to its BGP representation (a part of an Update message). * * Result: Length of the attribute block generated or -1 if not enough space. */ -uint -bgp_encode_attrs(struct bgp_proto *p, byte *w, ea_list *attrs, int remains) +int +bgp_encode_attrs(struct bgp_write_state *s, ea_list *attrs, byte *buf, byte *end) { - uint i, code, type, flags; - byte *start = w; - int len, rv; + byte *pos = buf; + int i, len; - for(i=0; i<attrs->count; i++) - { - eattr *a = &attrs->attrs[i]; - ASSERT(EA_PROTO(a->id) == EAP_BGP); - code = EA_ID(a->id); - -#ifdef IPV6 - /* When talking multiprotocol BGP, the NEXT_HOP attributes are used only temporarily. */ - if (code == BA_NEXT_HOP) - continue; -#endif - - /* When AS4-aware BGP speaker is talking to non-AS4-aware BGP speaker, - * we have to convert our 4B AS_PATH to 2B AS_PATH and send our AS_PATH - * as optional AS4_PATH attribute. - */ - if ((code == BA_AS_PATH) && (! p->as4_session)) - { - len = a->u.ptr->length; - - if (remains < (len + 4)) - goto err_no_buffer; - - /* Using temporary buffer because don't know a length of created attr - * and therefore a length of a header. Perhaps i should better always - * use BAF_EXT_LEN. */ - - byte buf[len]; - int new_used; - int nl = as_path_convert_to_old(a->u.ptr, buf, &new_used); - - DBG("BGP: Encoding old AS_PATH\n"); - rv = bgp_encode_attr_hdr(w, BAF_TRANSITIVE, BA_AS_PATH, nl); - ADVANCE(w, remains, rv); - memcpy(w, buf, nl); - ADVANCE(w, remains, nl); - - if (! new_used) - continue; - - if (remains < (len + 4)) - goto err_no_buffer; - - /* We should discard AS_CONFED_SEQUENCE or AS_CONFED_SET path segments - * here but we don't support confederations and such paths we already - * discarded in bgp_check_as_path(). - */ - - DBG("BGP: Encoding AS4_PATH\n"); - rv = bgp_encode_attr_hdr(w, BAF_OPTIONAL | BAF_TRANSITIVE, BA_AS4_PATH, len); - ADVANCE(w, remains, rv); - memcpy(w, a->u.ptr->data, len); - ADVANCE(w, remains, len); - - continue; - } - - /* The same issue with AGGREGATOR attribute */ - if ((code == BA_AGGREGATOR) && (! p->as4_session)) - { - int new_used; - - len = 6; - if (remains < (len + 3)) - goto err_no_buffer; - - rv = bgp_encode_attr_hdr(w, BAF_OPTIONAL | BAF_TRANSITIVE, BA_AGGREGATOR, len); - ADVANCE(w, remains, rv); - aggregator_convert_to_old(a->u.ptr, w, &new_used); - ADVANCE(w, remains, len); - - if (! new_used) - continue; - - len = 8; - if (remains < (len + 3)) - goto err_no_buffer; - - rv = bgp_encode_attr_hdr(w, BAF_OPTIONAL | BAF_TRANSITIVE, BA_AS4_AGGREGATOR, len); - ADVANCE(w, remains, rv); - memcpy(w, a->u.ptr->data, len); - ADVANCE(w, remains, len); - - continue; - } - - /* Standard path continues here ... */ - - type = a->type & EAF_TYPE_MASK; - flags = a->flags & (BAF_OPTIONAL | BAF_TRANSITIVE | BAF_PARTIAL); - len = bgp_get_attr_len(a); - - /* Skip empty sets */ - if (((type == EAF_TYPE_INT_SET) || (type == EAF_TYPE_EC_SET) || (type == EAF_TYPE_LC_SET)) && (len == 0)) - continue; - - if (remains < len + 4) - goto err_no_buffer; - - rv = bgp_encode_attr_hdr(w, flags, code, len); - ADVANCE(w, remains, rv); - - switch (type) - { - case EAF_TYPE_INT: - case EAF_TYPE_ROUTER_ID: - if (len == 4) - put_u32(w, a->u.data); - else - *w = a->u.data; - break; - case EAF_TYPE_IP_ADDRESS: - { - ip_addr ip = *(ip_addr *)a->u.ptr->data; - ipa_hton(ip); - memcpy(w, &ip, len); - break; - } - case EAF_TYPE_INT_SET: - case EAF_TYPE_LC_SET: - case EAF_TYPE_EC_SET: - { - u32 *z = int_set_get_data(a->u.ptr); - int i; - for(i=0; i<len; i+=4) - put_u32(w+i, *z++); - break; - } - case EAF_TYPE_OPAQUE: - case EAF_TYPE_AS_PATH: - memcpy(w, a->u.ptr->data, len); - break; - default: - bug("bgp_encode_attrs: unknown attribute type %02x", a->type); - } - ADVANCE(w, remains, len); - } - return w - start; + for (i = 0; i < attrs->count; i++) + { + len = bgp_encode_attr(s, &attrs->attrs[i], pos, end - pos); + + if (len < 0) + return -1; + + pos += len; + } - err_no_buffer: - return -1; + return pos - buf; } + /* -static void -bgp_init_prefix(struct fib_node *N) + * Attribute decoding + */ + +static void bgp_process_as4_attrs(ea_list **attrs, struct linpool *pool); + +static inline int +bgp_as_path_loopy(struct bgp_proto *p, ea_list *attrs, u32 asn) { - struct bgp_prefix *p = (struct bgp_prefix *) N; - p->bucket_node.next = NULL; + eattr *e = bgp_find_attr(attrs, BA_AS_PATH); + int num = p->cf->allow_local_as + 1; + return (e && (num > 0) && as_path_contains(e->u.ptr, asn, num)); } -*/ -static int -bgp_compare_u32(const u32 *x, const u32 *y) +static inline int +bgp_originator_id_loopy(struct bgp_proto *p, ea_list *attrs) { - return (*x < *y) ? -1 : (*x > *y) ? 1 : 0; + eattr *e = bgp_find_attr(attrs, BA_ORIGINATOR_ID); + return (e && (e->u.data == p->local_id)); } -static inline void -bgp_normalize_int_set(u32 *dest, u32 *src, unsigned cnt) +static inline int +bgp_cluster_list_loopy(struct bgp_proto *p, ea_list *attrs) { - memcpy(dest, src, sizeof(u32) * cnt); - qsort(dest, cnt, sizeof(u32), (int(*)(const void *, const void *)) bgp_compare_u32); + eattr *e = bgp_find_attr(attrs, BA_CLUSTER_LIST); + return (e && int_set_contains(e->u.ptr, p->rr_cluster_id)); } -static int -bgp_compare_ec(const u32 *xp, const u32 *yp) +static inline void +bgp_decode_attr(struct bgp_parse_state *s, uint code, uint flags, byte *data, uint len, ea_list **to) { - u64 x = ec_get(xp, 0); - u64 y = ec_get(yp, 0); - return (x < y) ? -1 : (x > y) ? 1 : 0; + /* Handle duplicate attributes; RFC 7606 3 (g) */ + if (BIT32_TEST(s->attrs_seen, code)) + { + if ((code == BA_MP_REACH_NLRI) || (code == BA_MP_UNREACH_NLRI)) + bgp_parse_error(s, 1); + else + DISCARD("Discarding duplicate attribute (code %u)", code); + } + BIT32_SET(s->attrs_seen, code); + + if (bgp_attr_known(code)) + { + const struct bgp_attr_desc *desc = &bgp_attr_table[code]; + + /* Handle conflicting flags; RFC 7606 3 (c) */ + if ((flags ^ desc->flags) & (BAF_OPTIONAL | BAF_TRANSITIVE)) + WITHDRAW("Malformed %s attribute - conflicting flags (%02x)", desc->name, flags); + + desc->decode(s, code, flags, data, len, to); + } + else /* Unknown attribute */ + { + if (!(flags & BAF_OPTIONAL)) + WITHDRAW("Unknown attribute (code %u) - conflicting flags (%02x)", code, flags); + + bgp_decode_unknown(s, code, flags, data, len, to); + } } -static inline void -bgp_normalize_ec_set(struct adata *ad, u32 *src, int internal) +/** + * bgp_decode_attrs - check and decode BGP attributes + * @s: BGP parse state + * @data: start of attribute block + * @len: length of attribute block + * + * This function takes a BGP attribute block (a part of an Update message), checks + * its consistency and converts it to a list of BIRD route attributes represented + * by an (uncached) &rta. + */ +ea_list * +bgp_decode_attrs(struct bgp_parse_state *s, byte *data, uint len) { - u32 *dst = int_set_get_data(ad); + struct bgp_proto *p = s->proto; + ea_list *attrs = NULL; + uint code, flags, alen; + byte *pos = data; - /* Remove non-transitive communities (EC_TBIT active) on external sessions */ - if (! internal) + /* Parse the attributes */ + while (len) + { + alen = 0; + + /* Read attribute type */ + if (len < 2) + goto framing_error; + flags = pos[0]; + code = pos[1]; + ADVANCE(pos, len, 2); + + /* Read attribute length */ + if (flags & BAF_EXT_LEN) { - int len = int_set_get_size(ad); - u32 *t = dst; - int i; - - for (i=0; i < len; i += 2) - { - if (src[i] & EC_TBIT) - continue; - - *t++ = src[i]; - *t++ = src[i+1]; - } - - ad->length = (t - dst) * 4; + if (len < 2) + goto framing_error; + alen = get_u16(pos); + ADVANCE(pos, len, 2); + } + else + { + if (len < 1) + goto framing_error; + alen = *pos; + ADVANCE(pos, len, 1); } - else - memcpy(dst, src, ad->length); - qsort(dst, ad->length / 8, 8, (int(*)(const void *, const void *)) bgp_compare_ec); -} + if (alen > len) + goto framing_error; -static int -bgp_compare_lc(const u32 *x, const u32 *y) -{ - if (x[0] != y[0]) - return (x[0] > y[0]) ? 1 : -1; - if (x[1] != y[1]) - return (x[1] > y[1]) ? 1 : -1; - if (x[2] != y[2]) - return (x[2] > y[2]) ? 1 : -1; - return 0; + DBG("Attr %02x %02x %u\n", code, flags, alen); + + bgp_decode_attr(s, code, flags, pos, alen, &attrs); + ADVANCE(pos, len, alen); + } + + if (s->err_withdraw) + goto withdraw; + + /* If there is no reachability NLRI, we are finished */ + if (!s->ip_reach_len && !s->mp_reach_len) + return NULL; + + + /* Handle missing mandatory attributes; RFC 7606 3 (d) */ + if (!BIT32_TEST(s->attrs_seen, BA_ORIGIN)) + { REPORT(NO_MANDATORY, "ORIGIN"); goto withdraw; } + + if (!BIT32_TEST(s->attrs_seen, BA_AS_PATH)) + { REPORT(NO_MANDATORY, "AS_PATH"); goto withdraw; } + + /* When receiving attributes from non-AS4-aware BGP speaker, we have to + reconstruct AS_PATH and AGGREGATOR attributes; RFC 6793 4.2.3 */ + if (!p->as4_session) + bgp_process_as4_attrs(&attrs, s->pool); + + /* Reject routes with our ASN in AS_PATH attribute */ + if (bgp_as_path_loopy(p, attrs, p->local_as)) + goto withdraw; + + /* Reject routes with our Confederation ID in AS_PATH attribute; RFC 5065 4.0 */ + if ((p->public_as != p->local_as) && bgp_as_path_loopy(p, attrs, p->public_as)) + goto withdraw; + + /* Reject routes with our Router ID in ORIGINATOR_ID attribute; RFC 4456 8 */ + if (p->is_internal && bgp_originator_id_loopy(p, attrs)) + goto withdraw; + + /* Reject routes with our Cluster ID in CLUSTER_LIST attribute; RFC 4456 8 */ + if (p->rr_client && bgp_cluster_list_loopy(p, attrs)) + goto withdraw; + + /* If there is no local preference, define one */ + if (!BIT32_TEST(s->attrs_seen, BA_LOCAL_PREF)) + bgp_set_attr_u32(&attrs, s->pool, BA_LOCAL_PREF, 0, p->cf->default_local_pref); + + return attrs; + + +framing_error: + /* RFC 7606 4 - handle attribute framing errors */ + REPORT("Malformed attribute list - framing error (%u/%u) at %d", + alen, len, (int) (pos - s->attrs)); + +withdraw: + /* RFC 7606 5.2 - handle missing NLRI during errors */ + if (!s->ip_reach_len && !s->mp_reach_len) + bgp_parse_error(s, 1); + + s->err_withdraw = 1; + return NULL; } -static inline void -bgp_normalize_lc_set(u32 *dest, u32 *src, unsigned cnt) + +/* + * Route bucket hash table + */ + +#define RBH_KEY(b) b->eattrs, b->hash +#define RBH_NEXT(b) b->next +#define RBH_EQ(a1,h1,a2,h2) h1 == h2 && ea_same(a1, a2) +#define RBH_FN(a,h) h + +#define RBH_REHASH bgp_rbh_rehash +#define RBH_PARAMS /8, *2, 2, 2, 8, 20 + + +HASH_DEFINE_REHASH_FN(RBH, struct bgp_bucket) + +void +bgp_init_bucket_table(struct bgp_channel *c) { - memcpy(dest, src, LCOMM_LENGTH * cnt); - qsort(dest, cnt, LCOMM_LENGTH, (int(*)(const void *, const void *)) bgp_compare_lc); + HASH_INIT(c->bucket_hash, c->pool, 8); + + init_list(&c->bucket_queue); + c->withdraw_bucket = NULL; } -static void -bgp_rehash_buckets(struct bgp_proto *p) +void +bgp_free_bucket_table(struct bgp_channel *c) { - struct bgp_bucket **old = p->bucket_hash; - struct bgp_bucket **new; - unsigned oldn = p->hash_size; - unsigned i, e, mask; + HASH_FREE(c->bucket_hash); + struct bgp_bucket *b; + WALK_LIST_FIRST(b, c->bucket_queue) + { + rem_node(&b->send_node); + mb_free(b); + } - p->hash_size = p->hash_limit; - DBG("BGP: Rehashing bucket table from %d to %d\n", oldn, p->hash_size); - p->hash_limit *= 4; - if (p->hash_limit >= 65536) - p->hash_limit = ~0; - new = p->bucket_hash = mb_allocz(p->p.pool, p->hash_size * sizeof(struct bgp_bucket *)); - mask = p->hash_size - 1; - for (i=0; i<oldn; i++) - while (b = old[i]) - { - old[i] = b->hash_next; - e = b->hash & mask; - b->hash_next = new[e]; - if (b->hash_next) - b->hash_next->hash_prev = b; - b->hash_prev = NULL; - new[e] = b; - } - mb_free(old); + mb_free(c->withdraw_bucket); + c->withdraw_bucket = NULL; } static struct bgp_bucket * -bgp_new_bucket(struct bgp_proto *p, ea_list *new, unsigned hash) +bgp_get_bucket(struct bgp_channel *c, ea_list *new) { - struct bgp_bucket *b; - unsigned ea_size = sizeof(ea_list) + new->count * sizeof(eattr); - unsigned ea_size_aligned = BIRD_ALIGN(ea_size, CPU_STRUCT_ALIGN); - unsigned size = sizeof(struct bgp_bucket) + ea_size_aligned; - unsigned i; + /* Hash and lookup */ + u32 hash = ea_hash(new); + struct bgp_bucket *b = HASH_FIND(c->bucket_hash, RBH, new, hash); + + if (b) + return b; + + uint ea_size = sizeof(ea_list) + new->count * sizeof(eattr); + uint ea_size_aligned = BIRD_ALIGN(ea_size, CPU_STRUCT_ALIGN); + uint size = sizeof(struct bgp_bucket) + ea_size_aligned; + uint i; byte *dest; - unsigned index = hash & (p->hash_size - 1); /* Gather total size of non-inline attributes */ - for (i=0; i<new->count; i++) - { - eattr *a = &new->attrs[i]; - if (!(a->type & EAF_EMBEDDED)) - size += BIRD_ALIGN(sizeof(struct adata) + a->u.ptr->length, CPU_STRUCT_ALIGN); - } + for (i = 0; i < new->count; i++) + { + eattr *a = &new->attrs[i]; - /* Create the bucket and hash it */ - b = mb_alloc(p->p.pool, size); - b->hash_next = p->bucket_hash[index]; - if (b->hash_next) - b->hash_next->hash_prev = b; - p->bucket_hash[index] = b; - b->hash_prev = NULL; - b->hash = hash; - add_tail(&p->bucket_queue, &b->send_node); + if (!(a->type & EAF_EMBEDDED)) + size += BIRD_ALIGN(sizeof(struct adata) + a->u.ptr->length, CPU_STRUCT_ALIGN); + } + + /* Create the bucket */ + b = mb_alloc(c->pool, size); init_list(&b->prefixes); + b->hash = hash; + + /* Copy list of extended attributes */ memcpy(b->eattrs, new, ea_size); - dest = ((byte *)b->eattrs) + ea_size_aligned; + dest = ((byte *) b->eattrs) + ea_size_aligned; /* Copy values of non-inline attributes */ - for (i=0; i<new->count; i++) + for (i = 0; i < new->count; i++) + { + eattr *a = &b->eattrs->attrs[i]; + + if (!(a->type & EAF_EMBEDDED)) { - eattr *a = &b->eattrs->attrs[i]; - if (!(a->type & EAF_EMBEDDED)) - { - struct adata *oa = a->u.ptr; - struct adata *na = (struct adata *) dest; - memcpy(na, oa, sizeof(struct adata) + oa->length); - a->u.ptr = na; - dest += BIRD_ALIGN(sizeof(struct adata) + na->length, CPU_STRUCT_ALIGN); - } + struct adata *oa = a->u.ptr; + struct adata *na = (struct adata *) dest; + memcpy(na, oa, sizeof(struct adata) + oa->length); + a->u.ptr = na; + dest += BIRD_ALIGN(sizeof(struct adata) + na->length, CPU_STRUCT_ALIGN); } + } - /* If needed, rehash */ - p->hash_count++; - if (p->hash_count > p->hash_limit) - bgp_rehash_buckets(p); + /* Insert the bucket to send queue and bucket hash */ + add_tail(&c->bucket_queue, &b->send_node); + HASH_INSERT2(c->bucket_hash, RBH, c->pool, b); return b; } static struct bgp_bucket * -bgp_get_bucket(struct bgp_proto *p, net *n, ea_list *attrs, int originate) +bgp_get_withdraw_bucket(struct bgp_channel *c) { - ea_list *new; - unsigned i, cnt, hash, code; - eattr *a, *d; - u32 seen = 0; - struct bgp_bucket *b; - - /* Merge the attribute list */ - new = alloca(ea_scan(attrs)); - ea_merge(attrs, new); - ea_sort(new); + if (!c->withdraw_bucket) + { + c->withdraw_bucket = mb_allocz(c->pool, sizeof(struct bgp_bucket)); + init_list(&c->withdraw_bucket->prefixes); + } - /* Normalize attributes */ - d = new->attrs; - cnt = new->count; - new->count = 0; - for(i=0; i<cnt; i++) - { - a = &new->attrs[i]; - if (EA_PROTO(a->id) != EAP_BGP) - continue; - code = EA_ID(a->id); - if (ATTR_KNOWN(code)) - { - if (!p->is_internal) - { - if (!bgp_attr_table[code].allow_in_ebgp) - continue; - if ((code == BA_LOCAL_PREF) && !p->cf->allow_local_pref) - continue; - } - /* The flags might have been zero if the attr was added by filters */ - a->flags = (a->flags & BAF_PARTIAL) | bgp_attr_table[code].expected_flags; - if (code < 32) - seen |= 1 << code; - } - else - { - /* Don't re-export unknown non-transitive attributes */ - if (!(a->flags & BAF_TRANSITIVE)) - continue; - } - *d = *a; - if ((d->type & EAF_ORIGINATED) && !originate && (d->flags & BAF_TRANSITIVE) && (d->flags & BAF_OPTIONAL)) - d->flags |= BAF_PARTIAL; - switch (d->type & EAF_TYPE_MASK) - { - case EAF_TYPE_INT_SET: - { - struct adata *z = alloca(sizeof(struct adata) + d->u.ptr->length); - z->length = d->u.ptr->length; - bgp_normalize_int_set((u32 *) z->data, (u32 *) d->u.ptr->data, z->length / 4); - d->u.ptr = z; - break; - } - case EAF_TYPE_EC_SET: - { - struct adata *z = alloca(sizeof(struct adata) + d->u.ptr->length); - z->length = d->u.ptr->length; - bgp_normalize_ec_set(z, (u32 *) d->u.ptr->data, p->is_internal); - d->u.ptr = z; - break; - } - case EAF_TYPE_LC_SET: - { - struct adata *z = alloca(sizeof(struct adata) + d->u.ptr->length); - z->length = d->u.ptr->length; - bgp_normalize_lc_set((u32 *) z->data, (u32 *) d->u.ptr->data, z->length / LCOMM_LENGTH); - d->u.ptr = z; - break; - } - default: ; - } - d++; - new->count++; - } + return c->withdraw_bucket; +} - /* Hash */ - hash = ea_hash(new); - for(b=p->bucket_hash[hash & (p->hash_size - 1)]; b; b=b->hash_next) - if (b->hash == hash && ea_same(b->eattrs, new)) - { - DBG("Found bucket.\n"); - return b; - } - - /* Ensure that there are all mandatory attributes */ - for(i=0; i<ARRAY_SIZE(bgp_mandatory_attrs); i++) - if (!(seen & (1 << bgp_mandatory_attrs[i]))) - { - log(L_ERR "%s: Mandatory attribute %s missing in route %I/%d", p->p.name, bgp_attr_table[bgp_mandatory_attrs[i]].name, n->n.prefix, n->n.pxlen); - return NULL; - } - - /* Check if next hop is valid */ - a = ea_find(new, EA_CODE(EAP_BGP, BA_NEXT_HOP)); - if (!a || ipa_equal(p->cf->remote_ip, *(ip_addr *)a->u.ptr->data)) - { - log(L_ERR "%s: Invalid NEXT_HOP attribute in route %I/%d", p->p.name, n->n.prefix, n->n.pxlen); - return NULL; - } +void +bgp_free_bucket(struct bgp_channel *c, struct bgp_bucket *b) +{ + rem_node(&b->send_node); + HASH_REMOVE2(c->bucket_hash, RBH, c->pool, b); + mb_free(b); +} - /* Create new bucket */ - DBG("Creating bucket.\n"); - return bgp_new_bucket(p, new, hash); +void +bgp_defer_bucket(struct bgp_channel *c, struct bgp_bucket *b) +{ + rem_node(&b->send_node); + add_tail(&c->bucket_queue, &b->send_node); } void -bgp_free_bucket(struct bgp_proto *p, struct bgp_bucket *buck) +bgp_withdraw_bucket(struct bgp_channel *c, struct bgp_bucket *b) { - if (buck->hash_next) - buck->hash_next->hash_prev = buck->hash_prev; - if (buck->hash_prev) - buck->hash_prev->hash_next = buck->hash_next; - else - p->bucket_hash[buck->hash & (p->hash_size-1)] = buck->hash_next; - mb_free(buck); + struct bgp_proto *p = (void *) c->c.proto; + struct bgp_bucket *wb = bgp_get_withdraw_bucket(c); + + log(L_ERR "%s: Attribute list too long", p->p.name); + while (!EMPTY_LIST(b->prefixes)) + { + struct bgp_prefix *px = HEAD(b->prefixes); + + log(L_ERR "%s: - withdrawing %N", p->p.name, &px->net); + rem_node(&px->buck_node); + add_tail(&wb->prefixes, &px->buck_node); + } } -/* Prefix hash table */ +/* + * Prefix hash table + */ -#define PXH_KEY(n1) n1->n.prefix, n1->n.pxlen, n1->path_id -#define PXH_NEXT(n) n->next -#define PXH_EQ(p1,l1,i1,p2,l2,i2) ipa_equal(p1, p2) && l1 == l2 && i1 == i2 -#define PXH_FN(p,l,i) ipa_hash32(p) ^ u32_hash((l << 16) ^ i) +#define PXH_KEY(px) px->net, px->path_id, px->hash +#define PXH_NEXT(px) px->next +#define PXH_EQ(n1,i1,h1,n2,i2,h2) h1 == h2 && i1 == i2 && net_equal(n1, n2) +#define PXH_FN(n,i,h) h #define PXH_REHASH bgp_pxh_rehash #define PXH_PARAMS /8, *2, 2, 2, 8, 20 @@ -929,308 +1309,282 @@ bgp_free_bucket(struct bgp_proto *p, struct bgp_bucket *buck) HASH_DEFINE_REHASH_FN(PXH, struct bgp_prefix) void -bgp_init_prefix_table(struct bgp_proto *p, u32 order) +bgp_init_prefix_table(struct bgp_channel *c) { - HASH_INIT(p->prefix_hash, p->p.pool, order); + HASH_INIT(c->prefix_hash, c->pool, 8); - p->prefix_slab = sl_new(p->p.pool, sizeof(struct bgp_prefix)); + uint alen = net_addr_length[c->c.net_type]; + c->prefix_slab = alen ? sl_new(c->pool, sizeof(struct bgp_prefix) + alen) : NULL; } void -bgp_free_prefix_table(struct bgp_proto *p) +bgp_free_prefix_table(struct bgp_channel *c) { - HASH_FREE(p->prefix_hash); + HASH_FREE(c->prefix_hash); - rfree(p->prefix_slab); - p->prefix_slab = NULL; + rfree(c->prefix_slab); + c->prefix_slab = NULL; } static struct bgp_prefix * -bgp_get_prefix(struct bgp_proto *p, ip_addr prefix, int pxlen, u32 path_id) +bgp_get_prefix(struct bgp_channel *c, net_addr *net, u32 path_id) { - struct bgp_prefix *bp = HASH_FIND(p->prefix_hash, PXH, prefix, pxlen, path_id); + u32 hash = net_hash(net) ^ u32_hash(path_id); + struct bgp_prefix *px = HASH_FIND(c->prefix_hash, PXH, net, path_id, hash); - if (bp) - return bp; + if (px) + { + rem_node(&px->buck_node); + return px; + } - bp = sl_alloc(p->prefix_slab); - bp->n.prefix = prefix; - bp->n.pxlen = pxlen; - bp->path_id = path_id; - bp->bucket_node.next = NULL; + if (c->prefix_slab) + px = sl_alloc(c->prefix_slab); + else + px = mb_alloc(c->pool, sizeof(struct bgp_prefix) + net->length); - HASH_INSERT2(p->prefix_hash, PXH, p->p.pool, bp); + px->buck_node.next = NULL; + px->buck_node.prev = NULL; + px->hash = hash; + px->path_id = path_id; + net_copy(px->net, net); - return bp; + HASH_INSERT2(c->prefix_hash, PXH, c->pool, px); + + return px; } void -bgp_free_prefix(struct bgp_proto *p, struct bgp_prefix *bp) +bgp_free_prefix(struct bgp_channel *c, struct bgp_prefix *px) { - HASH_REMOVE2(p->prefix_hash, PXH, p->p.pool, bp); - sl_free(p->prefix_slab, bp); + rem_node(&px->buck_node); + HASH_REMOVE2(c->prefix_hash, PXH, c->pool, px); + + if (c->prefix_slab) + sl_free(c->prefix_slab, px); + else + mb_free(px); } -void -bgp_rt_notify(struct proto *P, rtable *tbl UNUSED, net *n, rte *new, rte *old UNUSED, ea_list *attrs) +/* + * BGP protocol glue + */ + +int +bgp_import_control(struct proto *P, rte **new, ea_list **attrs UNUSED, struct linpool *pool UNUSED) { + rte *e = *new; + struct proto *SRC = e->attrs->src->proto; struct bgp_proto *p = (struct bgp_proto *) P; - struct bgp_bucket *buck; - struct bgp_prefix *px; - rte *key; - u32 path_id; + struct bgp_proto *src = (SRC->proto == &proto_bgp) ? (struct bgp_proto *) SRC : NULL; - DBG("BGP: Got route %I/%d %s\n", n->n.prefix, n->n.pxlen, new ? "up" : "down"); + /* Reject our routes */ + if (src == p) + return -1; - if (new) - { - key = new; - buck = bgp_get_bucket(p, n, attrs, new->attrs->source != RTS_BGP); - if (!buck) /* Inconsistent attribute list */ - return; - } - else - { - key = old; - if (!(buck = p->withdraw_bucket)) - { - buck = p->withdraw_bucket = mb_alloc(P->pool, sizeof(struct bgp_bucket)); - init_list(&buck->prefixes); - } - } - path_id = p->add_path_tx ? key->attrs->src->global_id : 0; - px = bgp_get_prefix(p, n->n.prefix, n->n.pxlen, path_id); - if (px->bucket_node.next) - { - DBG("\tRemoving old entry.\n"); - rem_node(&px->bucket_node); - } - add_tail(&buck->prefixes, &px->bucket_node); - bgp_schedule_packet(p->conn, PKT_UPDATE); -} + /* Accept non-BGP routes */ + if (src == NULL) + return 0; -static int -bgp_create_attrs(struct bgp_proto *p, rte *e, ea_list **attrs, struct linpool *pool) -{ - ea_list *ea = lp_alloc(pool, sizeof(ea_list) + 4*sizeof(eattr)); - rta *rta = e->attrs; - byte *z; + // XXXX: Check next hop AF - ea->next = *attrs; - *attrs = ea; - ea->flags = EALF_SORTED; - ea->count = 4; + /* IBGP route reflection, RFC 4456 */ + if (p->is_internal && src->is_internal && (p->local_as == src->local_as)) + { + /* Rejected unless configured as route reflector */ + if (!p->rr_client && !src->rr_client) + return -1; + + /* Generally, this should be handled when path is received, but we check it + also here as rr_cluster_id may be undefined or different in src. */ + if (p->rr_cluster_id && bgp_cluster_list_loopy(p, e->attrs->eattrs)) + return -1; + } - bgp_set_attr(ea->attrs, BA_ORIGIN, - ((rta->source == RTS_OSPF_EXT1) || (rta->source == RTS_OSPF_EXT2)) ? ORIGIN_INCOMPLETE : ORIGIN_IGP); + /* Handle well-known communities, RFC 1997 */ + struct eattr *c; + if (p->cf->interpret_communities && + (c = ea_find(e->attrs->eattrs, EA_CODE(EAP_BGP, BA_COMMUNITY)))) + { + struct adata *d = c->u.ptr; - if (p->is_internal) - bgp_set_attr_wa(ea->attrs+1, pool, BA_AS_PATH, 0); - else - { - z = bgp_set_attr_wa(ea->attrs+1, pool, BA_AS_PATH, 6); - z[0] = AS_PATH_SEQUENCE; - z[1] = 1; /* 1 AS */ - put_u32(z+2, p->local_as); - } + /* Do not export anywhere */ + if (int_set_contains(d, BGP_COMM_NO_ADVERTISE)) + return -1; - /* iBGP -> use gw, eBGP multi-hop -> use source_addr, - eBGP single-hop -> use gw if on the same iface */ - z = bgp_set_attr_wa(ea->attrs+2, pool, BA_NEXT_HOP, NEXT_HOP_LENGTH); - if (p->cf->next_hop_self || - rta->dest != RTD_ROUTER || - ipa_equal(rta->gw, IPA_NONE) || - ipa_is_link_local(rta->gw) || - (!p->is_internal && !p->cf->next_hop_keep && - (!p->neigh || (rta->iface != p->neigh->iface)))) - set_next_hop(z, p->source_addr); - else - set_next_hop(z, rta->gw); + /* Do not export outside of AS (or member-AS) */ + if (!p->is_internal && int_set_contains(d, BGP_COMM_NO_EXPORT_SUBCONFED)) + return -1; - bgp_set_attr(ea->attrs+3, BA_LOCAL_PREF, p->cf->default_local_pref); + /* Do not export outside of AS (or confederation) */ + if (!p->is_interior && int_set_contains(d, BGP_COMM_NO_EXPORT)) + return -1; + } - return 0; /* Leave decision to the filters */ + return 0; } -static inline int -bgp_as_path_loopy(struct bgp_proto *p, rta *a) -{ - int num = p->cf->allow_local_as + 1; - eattr *e = ea_find(a->eattrs, EA_CODE(EAP_BGP, BA_AS_PATH)); - return (e && (num > 0) && as_path_contains(e->u.ptr, p->local_as, num)); -} - -static inline int -bgp_originator_id_loopy(struct bgp_proto *p, rta *a) -{ - eattr *e = ea_find(a->eattrs, EA_CODE(EAP_BGP, BA_ORIGINATOR_ID)); - return (e && (e->u.data == p->local_id)); -} +static adata null_adata; /* adata of length 0 */ -static inline int -bgp_cluster_list_loopy(struct bgp_proto *p, rta *a) +static ea_list * +bgp_update_attrs(struct bgp_proto *p, struct bgp_channel *c, rte *e, ea_list *attrs0, struct linpool *pool) { - eattr *e = ea_find(a->eattrs, EA_CODE(EAP_BGP, BA_CLUSTER_LIST)); - return (e && p->rr_client && int_set_contains(e->u.ptr, p->rr_cluster_id)); -} + struct proto *SRC = e->attrs->src->proto; + struct bgp_proto *src = (SRC->proto == &proto_bgp) ? (void *) SRC : NULL; + struct bgp_export_state s = { .proto = p, .channel = c, .pool = pool, .src = src, .route = e, .mpls = c->desc->mpls }; + ea_list *attrs = attrs0; + eattr *a; + adata *ad; + /* ORIGIN attribute - mandatory, attach if missing */ + if (! bgp_find_attr(attrs0, BA_ORIGIN)) + bgp_set_attr_u32(&attrs, pool, BA_ORIGIN, 0, src ? ORIGIN_INCOMPLETE : ORIGIN_IGP); -static inline void -bgp_path_prepend(rte *e, ea_list **attrs, struct linpool *pool, u32 as) -{ - eattr *a = ea_find(e->attrs->eattrs, EA_CODE(EAP_BGP, BA_AS_PATH)); - bgp_attach_attr(attrs, pool, BA_AS_PATH, (uintptr_t) as_path_prepend(pool, a->u.ptr, as)); -} + /* AS_PATH attribute - mandatory */ + a = bgp_find_attr(attrs0, BA_AS_PATH); + ad = a ? a->u.ptr : &null_adata; -static inline void -bgp_cluster_list_prepend(rte *e, ea_list **attrs, struct linpool *pool, u32 cid) -{ - eattr *a = ea_find(e->attrs->eattrs, EA_CODE(EAP_BGP, BA_CLUSTER_LIST)); - bgp_attach_attr(attrs, pool, BA_CLUSTER_LIST, (uintptr_t) int_set_prepend(pool, a ? a->u.ptr : NULL, cid)); -} + /* AS_PATH attribute - strip AS_CONFED* segments outside confederation */ + if ((!p->cf->confederation || !p->is_interior) && as_path_contains_confed(ad)) + ad = as_path_strip_confed(pool, ad); -static int -bgp_update_attrs(struct bgp_proto *p, rte *e, ea_list **attrs, struct linpool *pool, int rr) -{ - eattr *a; + /* AS_PATH attribute - keep or prepend ASN */ + if (p->is_internal || + (p->rs_client && src && src->rs_client)) + { + /* IBGP or route server -> just ensure there is one */ + if (!a) + bgp_set_attr_ptr(&attrs, pool, BA_AS_PATH, 0, &null_adata); + } + else if (p->is_interior) + { + /* Confederation -> prepend ASN as AS_CONFED_SEQUENCE */ + ad = as_path_prepend2(pool, ad, AS_PATH_CONFED_SEQUENCE, p->public_as); + bgp_set_attr_ptr(&attrs, pool, BA_AS_PATH, 0, ad); + } + else /* Regular EBGP (no RS, no confederation) */ + { + /* Regular EBGP -> prepend ASN as regular sequence */ + ad = as_path_prepend2(pool, ad, AS_PATH_SEQUENCE, p->public_as); + bgp_set_attr_ptr(&attrs, pool, BA_AS_PATH, 0, ad); + + /* MULTI_EXIT_DESC attribute - accept only if set in export filter */ + a = bgp_find_attr(attrs0, BA_MULTI_EXIT_DISC); + if (a && !(a->type & EAF_FRESH)) + bgp_unset_attr(&attrs, pool, BA_MULTI_EXIT_DISC); + } - if (!p->is_internal && !p->rs_client) - { - bgp_path_prepend(e, attrs, pool, p->local_as); - - /* The MULTI_EXIT_DISC attribute received from a neighboring AS MUST NOT be - * propagated to other neighboring ASes. - * Perhaps it would be better to undefine it. - */ - a = ea_find(e->attrs->eattrs, EA_CODE(EAP_BGP, BA_MULTI_EXIT_DISC)); - if (a) - bgp_attach_attr(attrs, pool, BA_MULTI_EXIT_DISC, 0); - } + /* NEXT_HOP attribute - delegated to AF-specific hook */ + a = bgp_find_attr(attrs0, BA_NEXT_HOP); + bgp_update_next_hop(&s, a, &attrs); - /* iBGP -> keep next_hop, eBGP multi-hop -> use source_addr, - * eBGP single-hop -> keep next_hop if on the same iface. - * If the next_hop is zero (i.e. link-local), keep only if on the same iface. - * - * Note that same-iface-check uses iface from route, which is based on gw. - */ - a = ea_find(e->attrs->eattrs, EA_CODE(EAP_BGP, BA_NEXT_HOP)); - if (a && !p->cf->next_hop_self && - (p->cf->next_hop_keep || - (p->is_internal && ipa_nonzero(*((ip_addr *) a->u.ptr->data))) || - (p->neigh && (e->attrs->iface == p->neigh->iface)))) - { - /* Leave the original next hop attribute, will check later where does it point */ - } - else - { - /* Need to create new one */ - byte *b = bgp_attach_attr_wa(attrs, pool, BA_NEXT_HOP, NEXT_HOP_LENGTH); - set_next_hop(b, p->source_addr); - } + /* LOCAL_PREF attribute - required for IBGP, attach if missing */ + if (p->is_interior && ! bgp_find_attr(attrs0, BA_LOCAL_PREF)) + bgp_set_attr_u32(&attrs, pool, BA_LOCAL_PREF, 0, p->cf->default_local_pref); - if (rr) - { - /* Handling route reflection, RFC 4456 */ - struct bgp_proto *src = (struct bgp_proto *) e->attrs->src->proto; + /* IBGP route reflection, RFC 4456 */ + if (src && src->is_internal && p->is_internal && (src->local_as == p->local_as)) + { + /* ORIGINATOR_ID attribute - attach if not already set */ + if (! bgp_find_attr(attrs0, BA_ORIGINATOR_ID)) + bgp_set_attr_u32(&attrs, pool, BA_ORIGINATOR_ID, 0, src->remote_id); - a = ea_find(e->attrs->eattrs, EA_CODE(EAP_BGP, BA_ORIGINATOR_ID)); - if (!a) - bgp_attach_attr(attrs, pool, BA_ORIGINATOR_ID, src->remote_id); + /* CLUSTER_LIST attribute - prepend cluster ID */ + a = bgp_find_attr(attrs0, BA_CLUSTER_LIST); + ad = a ? a->u.ptr : NULL; - /* We attach proper cluster ID according to whether the route is entering or leaving the cluster */ - bgp_cluster_list_prepend(e, attrs, pool, src->rr_client ? src->rr_cluster_id : p->rr_cluster_id); + /* Prepend src cluster ID */ + if (src->rr_cluster_id) + ad = int_set_prepend(pool, ad, src->rr_cluster_id); - /* Two RR clients with different cluster ID, hmmm */ - if (src->rr_client && p->rr_client && (src->rr_cluster_id != p->rr_cluster_id)) - bgp_cluster_list_prepend(e, attrs, pool, p->rr_cluster_id); - } + /* Prepend dst cluster ID if src and dst clusters are different */ + if (p->rr_cluster_id && (src->rr_cluster_id != p->rr_cluster_id)) + ad = int_set_prepend(pool, ad, p->rr_cluster_id); - return 0; /* Leave decision to the filters */ -} + /* Should be at least one prepended cluster ID */ + bgp_set_attr_ptr(&attrs, pool, BA_CLUSTER_LIST, 0, ad); + } -static int -bgp_community_filter(struct bgp_proto *p, rte *e) -{ - eattr *a; - struct adata *d; + /* AS4_* transition attributes, RFC 6793 4.2.2 */ + if (! p->as4_session) + { + a = bgp_find_attr(attrs, BA_AS_PATH); + if (a && as_path_contains_as4(a->u.ptr)) + { + bgp_set_attr_ptr(&attrs, pool, BA_AS_PATH, 0, as_path_to_old(pool, a->u.ptr)); + bgp_set_attr_ptr(&attrs, pool, BA_AS4_PATH, 0, as_path_strip_confed(pool, a->u.ptr)); + } - /* Check if we aren't forbidden to export the route by communities */ - a = ea_find(e->attrs->eattrs, EA_CODE(EAP_BGP, BA_COMMUNITY)); - if (a) + a = bgp_find_attr(attrs, BA_AGGREGATOR); + if (a && aggregator_contains_as4(a->u.ptr)) { - d = a->u.ptr; - if (int_set_contains(d, BGP_COMM_NO_ADVERTISE)) - { - DBG("\tNO_ADVERTISE\n"); - return 1; - } - if (!p->is_internal && - (int_set_contains(d, BGP_COMM_NO_EXPORT) || - int_set_contains(d, BGP_COMM_NO_EXPORT_SUBCONFED))) - { - DBG("\tNO_EXPORT\n"); - return 1; - } + bgp_set_attr_ptr(&attrs, pool, BA_AGGREGATOR, 0, aggregator_to_old(pool, a->u.ptr)); + bgp_set_attr_ptr(&attrs, pool, BA_AS4_AGGREGATOR, 0, a->u.ptr); } + } - return 0; + /* + * Presence of mandatory attributes ORIGIN and AS_PATH is ensured by above + * conditions. Presence and validity of quasi-mandatory NEXT_HOP attribute + * should be checked in AF-specific hooks. + */ + + /* Apply per-attribute export hooks for validatation and normalization */ + return bgp_export_attrs(&s, attrs); } -int -bgp_import_control(struct proto *P, rte **new, ea_list **attrs, struct linpool *pool) +void +bgp_rt_notify(struct proto *P, struct channel *C, net *n, rte *new, rte *old, ea_list *attrs) { - rte *e = *new; - struct bgp_proto *p = (struct bgp_proto *) P; - struct bgp_proto *new_bgp = (e->attrs->src->proto->proto == &proto_bgp) ? - (struct bgp_proto *) e->attrs->src->proto : NULL; + struct bgp_proto *p = (void *) P; + struct bgp_channel *c = (void *) C; + struct bgp_bucket *buck; + struct bgp_prefix *px; + u32 path; - if (p == new_bgp) /* Poison reverse updates */ - return -1; - if (new_bgp) - { - /* We should check here for cluster list loop, because the receiving BGP instance - might have different cluster ID */ - if (bgp_cluster_list_loopy(p, e->attrs)) - return -1; - - if (p->cf->interpret_communities && bgp_community_filter(p, e)) - return -1; - - if (p->local_as == new_bgp->local_as && p->is_internal && new_bgp->is_internal) - { - /* Redistribution of internal routes with IBGP */ - if (p->rr_client || new_bgp->rr_client) - /* Route reflection, RFC 4456 */ - return bgp_update_attrs(p, e, attrs, pool, 1); - else - return -1; - } - else - return bgp_update_attrs(p, e, attrs, pool, 0); - } + if (new) + { + attrs = bgp_update_attrs(p, c, new, attrs, bgp_linpool2); + + /* If attributes are invalid, we fail back to withdraw */ + buck = attrs ? bgp_get_bucket(c, attrs) : bgp_get_withdraw_bucket(c); + path = new->attrs->src->global_id; + + lp_flush(bgp_linpool2); + } else - return bgp_create_attrs(p, e, attrs, pool); + { + buck = bgp_get_withdraw_bucket(c); + path = old->attrs->src->global_id; + } + + px = bgp_get_prefix(c, n->n.addr, c->add_path_tx ? path : 0); + add_tail(&buck->prefixes, &px->buck_node); + + bgp_schedule_packet(p->conn, c, PKT_UPDATE); } + static inline u32 bgp_get_neighbor(rte *r) { eattr *e = ea_find(r->attrs->eattrs, EA_CODE(EAP_BGP, BA_AS_PATH)); u32 as; - if (e && as_path_get_first(e->u.ptr, &as)) + if (e && as_path_get_first_regular(e->u.ptr, &as)) return as; - else - return ((struct bgp_proto *) r->attrs->src->proto)->remote_as; + + /* If AS_PATH is not defined, we treat rte as locally originated */ + struct bgp_proto *p = (void *) r->attrs->src->proto; + return p->cf->confederation ?: p->local_as; } static inline int rte_resolvable(rte *rt) { - int rd = rt->attrs->dest; - return (rd == RTD_ROUTER) || (rd == RTD_DEVICE) || (rd == RTD_MULTIPATH); + return rt->attrs->dest == RTD_UNICAST; } int @@ -1269,16 +1623,16 @@ bgp_rte_better(rte *new, rte *old) /* RFC 4271 9.1.2.2. a) Use AS path lengths */ if (new_bgp->cf->compare_path_lengths || old_bgp->cf->compare_path_lengths) - { - x = ea_find(new->attrs->eattrs, EA_CODE(EAP_BGP, BA_AS_PATH)); - y = ea_find(old->attrs->eattrs, EA_CODE(EAP_BGP, BA_AS_PATH)); - n = x ? as_path_getlen(x->u.ptr) : AS_PATH_MAXLEN; - o = y ? as_path_getlen(y->u.ptr) : AS_PATH_MAXLEN; - if (n < o) - return 1; - if (n > o) - return 0; - } + { + x = ea_find(new->attrs->eattrs, EA_CODE(EAP_BGP, BA_AS_PATH)); + y = ea_find(old->attrs->eattrs, EA_CODE(EAP_BGP, BA_AS_PATH)); + n = x ? as_path_getlen(x->u.ptr) : AS_PATH_MAXLEN; + o = y ? as_path_getlen(y->u.ptr) : AS_PATH_MAXLEN; + if (n < o) + return 1; + if (n > o) + return 0; + } /* RFC 4271 9.1.2.2. b) Use origins */ x = ea_find(new->attrs->eattrs, EA_CODE(EAP_BGP, BA_ORIGIN)); @@ -1303,21 +1657,21 @@ bgp_rte_better(rte *new, rte *old) */ if (new_bgp->cf->med_metric || old_bgp->cf->med_metric || (bgp_get_neighbor(new) == bgp_get_neighbor(old))) - { - x = ea_find(new->attrs->eattrs, EA_CODE(EAP_BGP, BA_MULTI_EXIT_DISC)); - y = ea_find(old->attrs->eattrs, EA_CODE(EAP_BGP, BA_MULTI_EXIT_DISC)); - n = x ? x->u.data : new_bgp->cf->default_med; - o = y ? y->u.data : old_bgp->cf->default_med; - if (n < o) - return 1; - if (n > o) - return 0; - } + { + x = ea_find(new->attrs->eattrs, EA_CODE(EAP_BGP, BA_MULTI_EXIT_DISC)); + y = ea_find(old->attrs->eattrs, EA_CODE(EAP_BGP, BA_MULTI_EXIT_DISC)); + n = x ? x->u.data : new_bgp->cf->default_med; + o = y ? y->u.data : old_bgp->cf->default_med; + if (n < o) + return 1; + if (n > o) + return 0; + } /* RFC 4271 9.1.2.2. d) Prefer external peers */ - if (new_bgp->is_internal > old_bgp->is_internal) + if (new_bgp->is_interior > old_bgp->is_interior) return 0; - if (new_bgp->is_internal < old_bgp->is_internal) + if (new_bgp->is_interior < old_bgp->is_interior) return 1; /* RFC 4271 9.1.2.2. e) Compare IGP metrics */ @@ -1329,7 +1683,7 @@ bgp_rte_better(rte *new, rte *old) return 0; /* RFC 4271 9.1.2.2. f) Compare BGP identifiers */ - /* RFC 4456 9. a) Use ORIGINATOR_ID instead of local neighor ID */ + /* RFC 4456 9. a) Use ORIGINATOR_ID instead of local neighbor ID */ x = ea_find(new->attrs->eattrs, EA_CODE(EAP_BGP, BA_ORIGINATOR_ID)); y = ea_find(old->attrs->eattrs, EA_CODE(EAP_BGP, BA_ORIGINATOR_ID)); n = x ? x->u.data : new_bgp->remote_id; @@ -1388,18 +1742,18 @@ bgp_rte_mergable(rte *pri, rte *sec) /* RFC 4271 9.1.2.2. a) Use AS path lengths */ if (pri_bgp->cf->compare_path_lengths || sec_bgp->cf->compare_path_lengths) - { - x = ea_find(pri->attrs->eattrs, EA_CODE(EAP_BGP, BA_AS_PATH)); - y = ea_find(sec->attrs->eattrs, EA_CODE(EAP_BGP, BA_AS_PATH)); - p = x ? as_path_getlen(x->u.ptr) : AS_PATH_MAXLEN; - s = y ? as_path_getlen(y->u.ptr) : AS_PATH_MAXLEN; + { + x = ea_find(pri->attrs->eattrs, EA_CODE(EAP_BGP, BA_AS_PATH)); + y = ea_find(sec->attrs->eattrs, EA_CODE(EAP_BGP, BA_AS_PATH)); + p = x ? as_path_getlen(x->u.ptr) : AS_PATH_MAXLEN; + s = y ? as_path_getlen(y->u.ptr) : AS_PATH_MAXLEN; - if (p != s) - return 0; + if (p != s) + return 0; -// if (DELTA(p, s) > pri_bgp->cf->relax_multipath) -// return 0; - } +// if (DELTA(p, s) > pri_bgp->cf->relax_multipath) +// return 0; + } /* RFC 4271 9.1.2.2. b) Use origins */ x = ea_find(pri->attrs->eattrs, EA_CODE(EAP_BGP, BA_ORIGIN)); @@ -1412,17 +1766,17 @@ bgp_rte_mergable(rte *pri, rte *sec) /* RFC 4271 9.1.2.2. c) Compare MED's */ if (pri_bgp->cf->med_metric || sec_bgp->cf->med_metric || (bgp_get_neighbor(pri) == bgp_get_neighbor(sec))) - { - x = ea_find(pri->attrs->eattrs, EA_CODE(EAP_BGP, BA_MULTI_EXIT_DISC)); - y = ea_find(sec->attrs->eattrs, EA_CODE(EAP_BGP, BA_MULTI_EXIT_DISC)); - p = x ? x->u.data : pri_bgp->cf->default_med; - s = y ? y->u.data : sec_bgp->cf->default_med; - if (p != s) - return 0; - } + { + x = ea_find(pri->attrs->eattrs, EA_CODE(EAP_BGP, BA_MULTI_EXIT_DISC)); + y = ea_find(sec->attrs->eattrs, EA_CODE(EAP_BGP, BA_MULTI_EXIT_DISC)); + p = x ? x->u.data : pri_bgp->cf->default_med; + s = y ? y->u.data : sec_bgp->cf->default_med; + if (p != s) + return 0; + } /* RFC 4271 9.1.2.2. d) Prefer external peers */ - if (pri_bgp->is_internal != sec_bgp->is_internal) + if (pri_bgp->is_interior != sec_bgp->is_interior) return 0; /* RFC 4271 9.1.2.2. e) Compare IGP metrics */ @@ -1437,7 +1791,6 @@ bgp_rte_mergable(rte *pri, rte *sec) } - static inline int same_group(rte *r, u32 lpref, u32 lasn) { @@ -1482,7 +1835,7 @@ bgp_rte_recalculate(rtable *table, net *net, rte *new, rte *old, rte *old_best) * that this fn is not called for them. * * The idea is simple, the implementation is more problematic, - * mostly because of optimizations in rte_recalculate() that + * mostly because of optimizations in rte_recalculate() that * avoids full recalculation in most cases. * * We can assume that at least one of new, old is non-NULL and both @@ -1494,14 +1847,14 @@ bgp_rte_recalculate(rtable *table, net *net, rte *new, rte *old, rte *old_best) /* If new and old are from different groups, we just process that as two independent events */ if (new && old && !same_group(old, lpref, lasn)) - { - int i1, i2; - i1 = bgp_rte_recalculate(table, net, NULL, old, old_best); - i2 = bgp_rte_recalculate(table, net, new, NULL, old_best); - return i1 || i2; - } + { + int i1, i2; + i1 = bgp_rte_recalculate(table, net, NULL, old, old_best); + i2 = bgp_rte_recalculate(table, net, new, NULL, old_best); + return i1 || i2; + } - /* + /* * We could find the best-in-group and then make some shortcuts like * in rte_recalculate, but as we would have to walk through all * net->routes just to find it, it is probably not worth. So we @@ -1513,35 +1866,35 @@ bgp_rte_recalculate(rtable *table, net *net, rte *new, rte *old, rte *old_best) new->u.bgp.suppressed = 1; if (old) + { + old_is_group_best = !old->u.bgp.suppressed; + old->u.bgp.suppressed = 1; + int new_is_better = new && bgp_rte_better(new, old); + + /* The first case - replace not best with worse (or remove not best) */ + if (!old_is_group_best && !new_is_better) + return 0; + + /* The second case - replace the best with better */ + if (old_is_group_best && new_is_better) { - old_is_group_best = !old->u.bgp.suppressed; - old->u.bgp.suppressed = 1; - int new_is_better = new && bgp_rte_better(new, old); - - /* The first case - replace not best with worse (or remove not best) */ - if (!old_is_group_best && !new_is_better) - return 0; - - /* The second case - replace the best with better */ - if (old_is_group_best && new_is_better) - { - /* new is best-in-group, the see discussion below - this is - a special variant of NBG && OBG. From OBG we can deduce - that same_group(old_best) iff (old == old_best) */ - new->u.bgp.suppressed = 0; - return (old == old_best); - } + /* new is best-in-group, the see discussion below - this is + a special variant of NBG && OBG. From OBG we can deduce + that same_group(old_best) iff (old == old_best) */ + new->u.bgp.suppressed = 0; + return (old == old_best); } + } /* The default case - find a new best-in-group route */ r = new; /* new may not be in the list */ for (s=net->routes; rte_is_valid(s); s=s->next) if (use_deterministic_med(s) && same_group(s, lpref, lasn)) - { - s->u.bgp.suppressed = 1; - if (!r || bgp_rte_better(s, r)) - r = s; - } + { + s->u.bgp.suppressed = 1; + if (!r || bgp_rte_better(s, r)) + r = s; + } /* Simple case - the last route in group disappears */ if (!r) @@ -1580,397 +1933,77 @@ bgp_rte_recalculate(rtable *table, net *net, rte *new, rte *old, rte *old_best) return old_is_group_best; } -static struct adata * -bgp_aggregator_convert_to_new(struct adata *old, struct linpool *pool) -{ - struct adata *newa = lp_alloc(pool, sizeof(struct adata) + 8); - newa->length = 8; - aggregator_convert_to_new(old, newa->data); - return newa; -} - -/* Take last req_as ASNs from path old2 (in 2B format), convert to 4B format - * and append path old4 (in 4B format). +/* + * Reconstruct AS_PATH and AGGREGATOR according to RFC 6793 4.2.3 */ -static struct adata * -bgp_merge_as_paths(struct adata *old2, struct adata *old4, int req_as, struct linpool *pool) -{ - byte buf[old2->length * 2]; - - int ol = as_path_convert_to_new(old2, buf, req_as); - int nl = ol + (old4 ? old4->length : 0); - - struct adata *newa = lp_alloc(pool, sizeof(struct adata) + nl); - newa->length = nl; - memcpy(newa->data, buf, ol); - if (old4) memcpy(newa->data + ol, old4->data, old4->length); - - return newa; -} - -static int -as4_aggregator_valid(struct adata *aggr) -{ - return aggr->length == 8; -} - - -/* Reconstruct 4B AS_PATH and AGGREGATOR according to RFC 4893 4.2.3 */ -static void -bgp_reconstruct_4b_atts(struct bgp_proto *p, rta *a, struct linpool *pool) -{ - eattr *p2 =ea_find(a->eattrs, EA_CODE(EAP_BGP, BA_AS_PATH)); - eattr *p4 =ea_find(a->eattrs, EA_CODE(EAP_BGP, BA_AS4_PATH)); - eattr *a2 =ea_find(a->eattrs, EA_CODE(EAP_BGP, BA_AGGREGATOR)); - eattr *a4 =ea_find(a->eattrs, EA_CODE(EAP_BGP, BA_AS4_AGGREGATOR)); - int a4_removed = 0; - - if (a4 && !as4_aggregator_valid(a4->u.ptr)) - { - log(L_WARN "%s: AS4_AGGREGATOR attribute is invalid, skipping attribute", p->p.name); - a4 = NULL; - a4_removed = 1; - } - - if (a2) - { - u32 a2_as = get_u16(a2->u.ptr->data); - - if (a4) - { - if (a2_as != AS_TRANS) - { - /* Routes were aggregated by old router and therefore AS4_PATH - * and AS4_AGGREGATOR is invalid - * - * Convert AS_PATH and AGGREGATOR to 4B format and finish. - */ - - a2->u.ptr = bgp_aggregator_convert_to_new(a2->u.ptr, pool); - p2->u.ptr = bgp_merge_as_paths(p2->u.ptr, NULL, AS_PATH_MAXLEN, pool); - - return; - } - else - { - /* Common case, use AS4_AGGREGATOR attribute */ - a2->u.ptr = a4->u.ptr; - } - } - else - { - /* Common case, use old AGGREGATOR attribute */ - a2->u.ptr = bgp_aggregator_convert_to_new(a2->u.ptr, pool); - - if ((a2_as == AS_TRANS) && !a4_removed) - log(L_WARN "%s: AGGREGATOR attribute contain AS_TRANS, but AS4_AGGREGATOR is missing", p->p.name); - } - } - else - if (a4) - log(L_WARN "%s: AS4_AGGREGATOR attribute received, but AGGREGATOR attribute is missing", p->p.name); - - int p2_len = as_path_getlen_int(p2->u.ptr, 2); - int p4_len = p4 ? validate_as4_path(p, p4->u.ptr) : -1; - - if (p4 && (p4_len < 0)) - log(L_WARN "%s: AS4_PATH attribute is malformed, skipping attribute", p->p.name); - - if ((p4_len <= 0) || (p2_len < p4_len)) - p2->u.ptr = bgp_merge_as_paths(p2->u.ptr, NULL, AS_PATH_MAXLEN, pool); - else - p2->u.ptr = bgp_merge_as_paths(p2->u.ptr, p4->u.ptr, p2_len - p4_len, pool); -} - static void -bgp_remove_as4_attrs(struct bgp_proto *p, rta *a) +bgp_process_as4_attrs(ea_list **attrs, struct linpool *pool) { - unsigned id1 = EA_CODE(EAP_BGP, BA_AS4_PATH); - unsigned id2 = EA_CODE(EAP_BGP, BA_AS4_AGGREGATOR); - ea_list **el = &(a->eattrs); - - /* We know that ea_lists constructed in bgp_decode attrs have one attribute per ea_list struct */ - while (*el != NULL) - { - unsigned fid = (*el)->attrs[0].id; - - if ((fid == id1) || (fid == id2)) - { - *el = (*el)->next; - if (p->as4_session) - log(L_WARN "%s: Unexpected AS4_* attributes received", p->p.name); - } - else - el = &((*el)->next); - } -} - -/** - * bgp_decode_attrs - check and decode BGP attributes - * @conn: connection - * @attr: start of attribute block - * @len: length of attribute block - * @pool: linear pool to make all the allocations in - * @mandatory: 1 iff presence of mandatory attributes has to be checked - * - * This function takes a BGP attribute block (a part of an Update message), checks - * its consistency and converts it to a list of BIRD route attributes represented - * by a &rta. - */ -struct rta * -bgp_decode_attrs(struct bgp_conn *conn, byte *attr, uint len, struct linpool *pool, int mandatory) -{ - struct bgp_proto *bgp = conn->bgp; - rta *a = lp_alloc(pool, sizeof(struct rta)); - uint flags, code, l, i, type; - int errcode; - byte *z, *attr_start; - byte seen[256/8]; - ea_list *ea; - struct adata *ad; - int withdraw = 0; - - bzero(a, sizeof(rta)); - a->source = RTS_BGP; - a->scope = SCOPE_UNIVERSE; - a->cast = RTC_UNICAST; - /* a->dest = RTD_ROUTER; -- set in bgp_set_next_hop() */ - a->from = bgp->cf->remote_ip; - - /* Parse the attributes */ - bzero(seen, sizeof(seen)); - DBG("BGP: Parsing attributes\n"); - while (len) - { - if (len < 2) - goto malformed; - attr_start = attr; - flags = *attr++; - code = *attr++; - len -= 2; - if (flags & BAF_EXT_LEN) - { - if (len < 2) - goto malformed; - l = get_u16(attr); - attr += 2; - len -= 2; - } - else - { - if (len < 1) - goto malformed; - l = *attr++; - len--; - } - if (l > len) - goto malformed; - len -= l; - z = attr; - attr += l; - DBG("Attr %02x %02x %d\n", code, flags, l); - if (seen[code/8] & (1 << (code%8))) - goto malformed; - if (ATTR_KNOWN(code)) - { - struct attr_desc *desc = &bgp_attr_table[code]; - if (desc->expected_length >= 0 && desc->expected_length != (int) l) - { errcode = 5; goto err; } - if ((desc->expected_flags ^ flags) & (BAF_OPTIONAL | BAF_TRANSITIVE)) - { errcode = 4; goto err; } - if (!bgp->is_internal) - { - if (!desc->allow_in_ebgp) - continue; - if ((code == BA_LOCAL_PREF) && !bgp->cf->allow_local_pref) - continue; - } - if (desc->validate) - { - errcode = desc->validate(bgp, z, l); - if (errcode > 0) - goto err; - if (errcode == IGNORE) - continue; - if (errcode <= WITHDRAW) - { - log(L_WARN "%s: Attribute %s is malformed, withdrawing update", - bgp->p.name, desc->name); - withdraw = 1; - } - } - else if (code == BA_AS_PATH) - { - /* Special case as it might also trim the attribute */ - if (validate_as_path(bgp, z, &l) < 0) - { errcode = 11; goto err; } - } - type = desc->type; - } - else /* Unknown attribute */ - { - if (!(flags & BAF_OPTIONAL)) - { errcode = 2; goto err; } - type = EAF_TYPE_OPAQUE; - } - - // Only OPTIONAL and TRANSITIVE attributes may have non-zero PARTIAL flag - // if (!((flags & BAF_OPTIONAL) && (flags & BAF_TRANSITIVE)) && (flags & BAF_PARTIAL)) - // { errcode = 4; goto err; } - - seen[code/8] |= (1 << (code%8)); - ea = lp_alloc(pool, sizeof(ea_list) + sizeof(eattr)); - ea->next = a->eattrs; - a->eattrs = ea; - ea->flags = 0; - ea->count = 1; - ea->attrs[0].id = EA_CODE(EAP_BGP, code); - ea->attrs[0].flags = flags; - ea->attrs[0].type = type; - if (type & EAF_EMBEDDED) - ad = NULL; - else - { - ad = lp_alloc(pool, sizeof(struct adata) + l); - ea->attrs[0].u.ptr = ad; - ad->length = l; - memcpy(ad->data, z, l); - } - switch (type) - { - case EAF_TYPE_ROUTER_ID: - case EAF_TYPE_INT: - if (l == 1) - ea->attrs[0].u.data = *z; - else - ea->attrs[0].u.data = get_u32(z); - break; - case EAF_TYPE_IP_ADDRESS: - ipa_ntoh(*(ip_addr *)ad->data); - break; - case EAF_TYPE_INT_SET: - case EAF_TYPE_LC_SET: - case EAF_TYPE_EC_SET: - { - u32 *z = (u32 *) ad->data; - for(i=0; i<ad->length/4; i++) - z[i] = ntohl(z[i]); - break; - } - } - } - - if (withdraw) - goto withdraw; + eattr *p2 = bgp_find_attr(*attrs, BA_AS_PATH); + eattr *p4 = bgp_find_attr(*attrs, BA_AS4_PATH); + eattr *a2 = bgp_find_attr(*attrs, BA_AGGREGATOR); + eattr *a4 = bgp_find_attr(*attrs, BA_AS4_AGGREGATOR); -#ifdef IPV6 - /* If we received MP_REACH_NLRI we should check mandatory attributes */ - if (bgp->mp_reach_len != 0) - mandatory = 1; -#endif + /* First, unset AS4_* attributes */ + if (p4) bgp_unset_attr(attrs, pool, BA_AS4_PATH); + if (a4) bgp_unset_attr(attrs, pool, BA_AS4_AGGREGATOR); - /* If there is no (reachability) NLRI, we should exit now */ - if (! mandatory) - return a; - - /* Check if all mandatory attributes are present */ - for(i=0; i < ARRAY_SIZE(bgp_mandatory_attrs); i++) - { - code = bgp_mandatory_attrs[i]; - if (!(seen[code/8] & (1 << (code%8)))) - { - bgp_error(conn, 3, 3, &bgp_mandatory_attrs[i], 1); - return NULL; - } - } - - /* When receiving attributes from non-AS4-aware BGP speaker, - * we have to reconstruct 4B AS_PATH and AGGREGATOR attributes - */ - if (! bgp->as4_session) - bgp_reconstruct_4b_atts(bgp, a, pool); - - bgp_remove_as4_attrs(bgp, a); - - /* If the AS path attribute contains our AS, reject the routes */ - if (bgp_as_path_loopy(bgp, a)) - goto withdraw; - - /* Two checks for IBGP loops caused by route reflection, RFC 4456 */ - if (bgp_originator_id_loopy(bgp, a) || - bgp_cluster_list_loopy(bgp, a)) - goto withdraw; + /* Handle AGGREGATOR attribute */ + if (a2 && a4) + { + u32 a2_asn = get_u32(a2->u.ptr->data); - /* If there's no local preference, define one */ - if (!(seen[0] & (1 << BA_LOCAL_PREF))) - bgp_attach_attr(&a->eattrs, pool, BA_LOCAL_PREF, bgp->cf->default_local_pref); + /* If routes were aggregated by an old router, then AS4_PATH and + AS4_AGGREGATOR are invalid. In that case we give up. */ + if (a2_asn != AS_TRANS) + return; - return a; + /* Use AS4_AGGREGATOR instead of AGGREGATOR */ + a2->u.ptr = a4->u.ptr; + } -withdraw: - return NULL; + /* Handle AS_PATH attribute */ + if (p2 && p4) + { + /* Both as_path_getlen() and as_path_cut() take AS_CONFED* as zero length */ + int p2_len = as_path_getlen(p2->u.ptr); + int p4_len = as_path_getlen(p4->u.ptr); -malformed: - bgp_error(conn, 3, 1, NULL, 0); - return NULL; + /* AS_PATH is too short, give up */ + if (p2_len < p4_len) + return; -err: - bgp_error(conn, 3, errcode, attr_start, z+l-attr_start); - return NULL; + /* Merge AS_PATH and AS4_PATH */ + as_path_cut(p2->u.ptr, p2_len - p4_len); + p2->u.ptr = as_path_merge(pool, p2->u.ptr, p4->u.ptr); + } } int bgp_get_attr(eattr *a, byte *buf, int buflen) { uint i = EA_ID(a->id); - struct attr_desc *d; + const struct bgp_attr_desc *d; int len; - if (ATTR_KNOWN(i)) + if (bgp_attr_known(i)) + { + d = &bgp_attr_table[i]; + len = bsprintf(buf, "%s", d->name); + buf += len; + if (d->format) { - d = &bgp_attr_table[i]; - len = bsprintf(buf, "%s", d->name); - buf += len; - if (d->format) - { - *buf++ = ':'; - *buf++ = ' '; - d->format(a, buf, buflen - len - 2); - return GA_FULL; - } - return GA_NAME; + *buf++ = ':'; + *buf++ = ' '; + d->format(a, buf, buflen - len - 2); + return GA_FULL; } - bsprintf(buf, "%02x%s", i, (a->flags & BAF_TRANSITIVE) ? " [t]" : ""); - return GA_NAME; -} - -void -bgp_init_bucket_table(struct bgp_proto *p) -{ - p->hash_size = 256; - p->hash_limit = p->hash_size * 4; - p->bucket_hash = mb_allocz(p->p.pool, p->hash_size * sizeof(struct bgp_bucket *)); - init_list(&p->bucket_queue); - p->withdraw_bucket = NULL; - // fib_init(&p->prefix_fib, p->p.pool, sizeof(struct bgp_prefix), 0, bgp_init_prefix); -} - -void -bgp_free_bucket_table(struct bgp_proto *p) -{ - mb_free(p->bucket_hash); - p->bucket_hash = NULL; - - struct bgp_bucket *b; - WALK_LIST_FIRST(b, p->bucket_queue) - { - rem_node(&b->send_node); - mb_free(b); + return GA_NAME; } - mb_free(p->withdraw_bucket); - p->withdraw_bucket = NULL; + bsprintf(buf, "%02x%s", i, (a->flags & BAF_TRANSITIVE) ? " [t]" : ""); + return GA_NAME; } void @@ -1986,14 +2019,14 @@ bgp_get_route_info(rte *e, byte *buf, ea_list *attrs) buf += bsprintf(buf, "-"); if (e->attrs->hostentry) - { - if (!rte_resolvable(e)) - buf += bsprintf(buf, "/-"); - else if (e->attrs->igp_metric >= IGP_METRIC_UNKNOWN) - buf += bsprintf(buf, "/?"); - else - buf += bsprintf(buf, "/%d", e->attrs->igp_metric); - } + { + if (!rte_resolvable(e)) + buf += bsprintf(buf, "/-"); + else if (e->attrs->igp_metric >= IGP_METRIC_UNKNOWN) + buf += bsprintf(buf, "/?"); + else + buf += bsprintf(buf, "/%d", e->attrs->igp_metric); + } buf += bsprintf(buf, ") ["); if (p && as_path_get_last(p->u.ptr, &origas)) |