diff options
Diffstat (limited to 'sysdep/linux/netlink.c')
| -rw-r--r-- | sysdep/linux/netlink.c | 1149 |
1 files changed, 1149 insertions, 0 deletions
diff --git a/sysdep/linux/netlink.c b/sysdep/linux/netlink.c new file mode 100644 index 00000000..eaaf048e --- /dev/null +++ b/sysdep/linux/netlink.c @@ -0,0 +1,1149 @@ +/* + * BIRD -- Linux Netlink Interface + * + * (c) 1999--2000 Martin Mares <mj@ucw.cz> + * + * Can be freely distributed and used under the terms of the GNU GPL. + */ + +#include <stdio.h> +#include <fcntl.h> +#include <sys/socket.h> +#include <sys/uio.h> +#include <errno.h> + +#undef LOCAL_DEBUG + +#include "nest/bird.h" +#include "nest/route.h" +#include "nest/protocol.h" +#include "nest/iface.h" +#include "lib/alloca.h" +#include "lib/timer.h" +#include "lib/unix.h" +#include "lib/krt.h" +#include "lib/socket.h" +#include "lib/string.h" +#include "conf/conf.h" + +#include <asm/types.h> +#include <linux/if.h> +#include <linux/netlink.h> +#include <linux/rtnetlink.h> + +#ifndef MSG_TRUNC /* Hack: Several versions of glibc miss this one :( */ +#define MSG_TRUNC 0x20 +#endif + +#ifndef IFF_LOWER_UP +#define IFF_LOWER_UP 0x10000 +#endif + +/* + * Synchronous Netlink interface + */ + +struct nl_sock +{ + int fd; + u32 seq; + byte *rx_buffer; /* Receive buffer */ + struct nlmsghdr *last_hdr; /* Recently received packet */ + unsigned int last_size; +}; + +#define NL_RX_SIZE 8192 + +static struct nl_sock nl_scan = {.fd = -1}; /* Netlink socket for synchronous scan */ +static struct nl_sock nl_req = {.fd = -1}; /* Netlink socket for requests */ + +static void +nl_open_sock(struct nl_sock *nl) +{ + if (nl->fd < 0) + { + nl->fd = socket(PF_NETLINK, SOCK_RAW, NETLINK_ROUTE); + if (nl->fd < 0) + die("Unable to open rtnetlink socket: %m"); + nl->seq = now; + nl->rx_buffer = xmalloc(NL_RX_SIZE); + nl->last_hdr = NULL; + nl->last_size = 0; + } +} + +static void +nl_open(void) +{ + nl_open_sock(&nl_scan); + nl_open_sock(&nl_req); +} + +static void +nl_send(struct nl_sock *nl, struct nlmsghdr *nh) +{ + struct sockaddr_nl sa; + + memset(&sa, 0, sizeof(sa)); + sa.nl_family = AF_NETLINK; + nh->nlmsg_pid = 0; + nh->nlmsg_seq = ++(nl->seq); + if (sendto(nl->fd, nh, nh->nlmsg_len, 0, (struct sockaddr *)&sa, sizeof(sa)) < 0) + die("rtnetlink sendto: %m"); + nl->last_hdr = NULL; +} + +static void +nl_request_dump(int cmd) +{ + struct { + struct nlmsghdr nh; + struct rtgenmsg g; + } req; + req.nh.nlmsg_type = cmd; + req.nh.nlmsg_len = sizeof(req); + req.nh.nlmsg_flags = NLM_F_REQUEST | NLM_F_DUMP; + /* Is it important which PF_* is used for link-level interface scan? + It seems that some information is available only when PF_INET is used. */ + req.g.rtgen_family = (cmd == RTM_GETLINK) ? PF_INET : BIRD_PF; + nl_send(&nl_scan, &req.nh); +} + +static struct nlmsghdr * +nl_get_reply(struct nl_sock *nl) +{ + for(;;) + { + if (!nl->last_hdr) + { + struct iovec iov = { nl->rx_buffer, NL_RX_SIZE }; + struct sockaddr_nl sa; + struct msghdr m = { (struct sockaddr *) &sa, sizeof(sa), &iov, 1, NULL, 0, 0 }; + int x = recvmsg(nl->fd, &m, 0); + if (x < 0) + die("nl_get_reply: %m"); + if (sa.nl_pid) /* It isn't from the kernel */ + { + DBG("Non-kernel packet\n"); + continue; + } + nl->last_size = x; + nl->last_hdr = (void *) nl->rx_buffer; + if (m.msg_flags & MSG_TRUNC) + bug("nl_get_reply: got truncated reply which should be impossible"); + } + if (NLMSG_OK(nl->last_hdr, nl->last_size)) + { + struct nlmsghdr *h = nl->last_hdr; + nl->last_hdr = NLMSG_NEXT(h, nl->last_size); + if (h->nlmsg_seq != nl->seq) + { + log(L_WARN "nl_get_reply: Ignoring out of sequence netlink packet (%x != %x)", + h->nlmsg_seq, nl->seq); + continue; + } + return h; + } + if (nl->last_size) + log(L_WARN "nl_get_reply: Found packet remnant of size %d", nl->last_size); + nl->last_hdr = NULL; + } +} + +static struct rate_limit rl_netlink_err; + +static int +nl_error(struct nlmsghdr *h) +{ + struct nlmsgerr *e; + int ec; + + if (h->nlmsg_len < NLMSG_LENGTH(sizeof(struct nlmsgerr))) + { + log(L_WARN "Netlink: Truncated error message received"); + return ENOBUFS; + } + e = (struct nlmsgerr *) NLMSG_DATA(h); + ec = -e->error; + if (ec) + log_rl(&rl_netlink_err, L_WARN "Netlink: %s", strerror(ec)); + return ec; +} + +static struct nlmsghdr * +nl_get_scan(void) +{ + struct nlmsghdr *h = nl_get_reply(&nl_scan); + + if (h->nlmsg_type == NLMSG_DONE) + return NULL; + if (h->nlmsg_type == NLMSG_ERROR) + { + nl_error(h); + return NULL; + } + return h; +} + +static int +nl_exchange(struct nlmsghdr *pkt) +{ + struct nlmsghdr *h; + + nl_send(&nl_req, pkt); + for(;;) + { + h = nl_get_reply(&nl_req); + if (h->nlmsg_type == NLMSG_ERROR) + break; + log(L_WARN "nl_exchange: Unexpected reply received"); + } + return nl_error(h) ? -1 : 0; +} + +/* + * Netlink attributes + */ + +static int nl_attr_len; + +static void * +nl_checkin(struct nlmsghdr *h, int lsize) +{ + nl_attr_len = h->nlmsg_len - NLMSG_LENGTH(lsize); + if (nl_attr_len < 0) + { + log(L_ERR "nl_checkin: underrun by %d bytes", -nl_attr_len); + return NULL; + } + return NLMSG_DATA(h); +} + +static int +nl_parse_attrs(struct rtattr *a, struct rtattr **k, int ksize) +{ + int max = ksize / sizeof(struct rtattr *); + bzero(k, ksize); + while (RTA_OK(a, nl_attr_len)) + { + if (a->rta_type < max) + k[a->rta_type] = a; + a = RTA_NEXT(a, nl_attr_len); + } + if (nl_attr_len) + { + log(L_ERR "nl_parse_attrs: remnant of size %d", nl_attr_len); + return 0; + } + else + return 1; +} + +void +nl_add_attr(struct nlmsghdr *h, unsigned bufsize, unsigned code, + void *data, unsigned dlen) +{ + unsigned len = RTA_LENGTH(dlen); + unsigned pos = NLMSG_ALIGN(h->nlmsg_len); + struct rtattr *a; + + if (pos + len > bufsize) + bug("nl_add_attr: packet buffer overflow"); + a = (struct rtattr *)((char *)h + pos); + a->rta_type = code; + a->rta_len = len; + h->nlmsg_len = pos + len; + memcpy(RTA_DATA(a), data, dlen); +} + +static inline void +nl_add_attr_u32(struct nlmsghdr *h, unsigned bufsize, int code, u32 data) +{ + nl_add_attr(h, bufsize, code, &data, 4); +} + +static inline void +nl_add_attr_ipa(struct nlmsghdr *h, unsigned bufsize, int code, ip_addr ipa) +{ + ipa_hton(ipa); + nl_add_attr(h, bufsize, code, &ipa, sizeof(ipa)); +} + +#define RTNH_SIZE (sizeof(struct rtnexthop) + sizeof(struct rtattr) + sizeof(ip_addr)) + +static inline void +add_mpnexthop(char *buf, ip_addr ipa, unsigned iface, unsigned char weight) +{ + struct rtnexthop *nh = (void *) buf; + struct rtattr *rt = (void *) (buf + sizeof(*nh)); + nh->rtnh_len = RTNH_SIZE; + nh->rtnh_flags = 0; + nh->rtnh_hops = weight; + nh->rtnh_ifindex = iface; + rt->rta_len = sizeof(*rt) + sizeof(ipa); + rt->rta_type = RTA_GATEWAY; + ipa_hton(ipa); + memcpy(buf + sizeof(*nh) + sizeof(*rt), &ipa, sizeof(ipa)); +} + + +static void +nl_add_multipath(struct nlmsghdr *h, unsigned bufsize, struct mpnh *nh) +{ + unsigned len = sizeof(struct rtattr); + unsigned pos = NLMSG_ALIGN(h->nlmsg_len); + char *buf = (char *)h + pos; + struct rtattr *rt = (void *) buf; + buf += len; + + for (; nh; nh = nh->next) + { + len += RTNH_SIZE; + if (pos + len > bufsize) + bug("nl_add_multipath: packet buffer overflow"); + + add_mpnexthop(buf, nh->gw, nh->iface->index, nh->weight); + buf += RTNH_SIZE; + } + + rt->rta_type = RTA_MULTIPATH; + rt->rta_len = len; + h->nlmsg_len = pos + len; +} + + +static struct mpnh * +nl_parse_multipath(struct krt_proto *p, struct rtattr *ra) +{ + /* Temporary buffer for multicast nexthops */ + static struct mpnh *nh_buffer; + static int nh_buf_size; /* in number of structures */ + static int nh_buf_used; + + struct rtattr *a[RTA_CACHEINFO+1]; + struct rtnexthop *nh = RTA_DATA(ra); + struct mpnh *rv, *first, **last; + int len = RTA_PAYLOAD(ra); + + first = NULL; + last = &first; + nh_buf_used = 0; + + while (len) + { + /* Use RTNH_OK(nh,len) ?? */ + if ((len < sizeof(*nh)) || (len < nh->rtnh_len)) + return NULL; + + if (nh_buf_used == nh_buf_size) + { + nh_buf_size = nh_buf_size ? (nh_buf_size * 2) : 4; + nh_buffer = xrealloc(nh_buffer, nh_buf_size * sizeof(struct mpnh)); + } + *last = rv = nh_buffer + nh_buf_used++; + rv->next = NULL; + last = &(rv->next); + + rv->weight = nh->rtnh_hops; + rv->iface = if_find_by_index(nh->rtnh_ifindex); + if (!rv->iface) + return NULL; + + /* Nonexistent RTNH_PAYLOAD ?? */ + nl_attr_len = nh->rtnh_len - RTNH_LENGTH(0); + nl_parse_attrs(RTNH_DATA(nh), a, sizeof(a)); + if (a[RTA_GATEWAY]) + { + if (RTA_PAYLOAD(a[RTA_GATEWAY]) != sizeof(ip_addr)) + return NULL; + + memcpy(&rv->gw, RTA_DATA(a[RTA_GATEWAY]), sizeof(ip_addr)); + ipa_ntoh(rv->gw); + + neighbor *ng = neigh_find2(&p->p, &rv->gw, rv->iface, + (nh->rtnh_flags & RTNH_F_ONLINK) ? NEF_ONLINK : 0); + if (!ng || (ng->scope == SCOPE_HOST)) + return NULL; + } + else + return NULL; + + len -= NLMSG_ALIGN(nh->rtnh_len); + nh = RTNH_NEXT(nh); + } + + return first; +} + + +/* + * Scanning of interfaces + */ + +static void +nl_parse_link(struct nlmsghdr *h, int scan) +{ + struct ifinfomsg *i; + struct rtattr *a[IFLA_WIRELESS+1]; + int new = h->nlmsg_type == RTM_NEWLINK; + struct iface f = {}; + struct iface *ifi; + char *name; + u32 mtu; + unsigned int fl; + + if (!(i = nl_checkin(h, sizeof(*i))) || !nl_parse_attrs(IFLA_RTA(i), a, sizeof(a))) + return; + if (!a[IFLA_IFNAME] || RTA_PAYLOAD(a[IFLA_IFNAME]) < 2 || + !a[IFLA_MTU] || RTA_PAYLOAD(a[IFLA_MTU]) != 4) + { + if (scan || !a[IFLA_WIRELESS]) + log(L_ERR "nl_parse_link: Malformed message received"); + return; + } + name = RTA_DATA(a[IFLA_IFNAME]); + memcpy(&mtu, RTA_DATA(a[IFLA_MTU]), sizeof(u32)); + + ifi = if_find_by_index(i->ifi_index); + if (!new) + { + DBG("KIF: IF%d(%s) goes down\n", i->ifi_index, name); + if (!ifi) + return; + + if_delete(ifi); + } + else + { + DBG("KIF: IF%d(%s) goes up (mtu=%d,flg=%x)\n", i->ifi_index, name, mtu, i->ifi_flags); + if (ifi && strncmp(ifi->name, name, sizeof(ifi->name)-1)) + if_delete(ifi); + + strncpy(f.name, name, sizeof(f.name)-1); + f.index = i->ifi_index; + f.mtu = mtu; + + fl = i->ifi_flags; + if (fl & IFF_UP) + f.flags |= IF_ADMIN_UP; + if (fl & IFF_LOWER_UP) + f.flags |= IF_LINK_UP; + if (fl & IFF_LOOPBACK) /* Loopback */ + f.flags |= IF_MULTIACCESS | IF_LOOPBACK | IF_IGNORE; + else if (fl & IFF_POINTOPOINT) /* PtP */ + f.flags |= IF_MULTICAST; + else if (fl & IFF_BROADCAST) /* Broadcast */ + f.flags |= IF_MULTIACCESS | IF_BROADCAST | IF_MULTICAST; + else + f.flags |= IF_MULTIACCESS; /* NBMA */ + if_update(&f); + } +} + +static void +nl_parse_addr(struct nlmsghdr *h) +{ + struct ifaddrmsg *i; + struct rtattr *a[IFA_ANYCAST+1]; + int new = h->nlmsg_type == RTM_NEWADDR; + struct ifa ifa; + struct iface *ifi; + int scope; + + if (!(i = nl_checkin(h, sizeof(*i))) || !nl_parse_attrs(IFA_RTA(i), a, sizeof(a))) + return; + if (i->ifa_family != BIRD_AF) + return; + if (!a[IFA_ADDRESS] || RTA_PAYLOAD(a[IFA_ADDRESS]) != sizeof(ip_addr) +#ifdef IPV6 + || a[IFA_LOCAL] && RTA_PAYLOAD(a[IFA_LOCAL]) != sizeof(ip_addr) +#else + || !a[IFA_LOCAL] || RTA_PAYLOAD(a[IFA_LOCAL]) != sizeof(ip_addr) + || (a[IFA_BROADCAST] && RTA_PAYLOAD(a[IFA_BROADCAST]) != sizeof(ip_addr)) +#endif + ) + { + log(L_ERR "nl_parse_addr: Malformed message received"); + return; + } + + ifi = if_find_by_index(i->ifa_index); + if (!ifi) + { + log(L_ERR "KIF: Received address message for unknown interface %d", i->ifa_index); + return; + } + + bzero(&ifa, sizeof(ifa)); + ifa.iface = ifi; + if (i->ifa_flags & IFA_F_SECONDARY) + ifa.flags |= IA_SECONDARY; + + /* IFA_LOCAL can be unset for IPv6 interfaces */ + memcpy(&ifa.ip, RTA_DATA(a[IFA_LOCAL] ? : a[IFA_ADDRESS]), sizeof(ifa.ip)); + ipa_ntoh(ifa.ip); + ifa.pxlen = i->ifa_prefixlen; + if (i->ifa_prefixlen > BITS_PER_IP_ADDRESS) + { + log(L_ERR "KIF: Invalid prefix length for interface %s: %d", ifi->name, i->ifa_prefixlen); + new = 0; + } + if (i->ifa_prefixlen == BITS_PER_IP_ADDRESS) + { + ip_addr addr; + memcpy(&addr, RTA_DATA(a[IFA_ADDRESS]), sizeof(addr)); + ipa_ntoh(addr); + ifa.prefix = ifa.brd = addr; + + /* It is either a host address or a peer address */ + if (ipa_equal(ifa.ip, addr)) + ifa.flags |= IA_HOST; + else + { + ifa.flags |= IA_PEER; + ifa.opposite = addr; + } + } + else + { + ip_addr netmask = ipa_mkmask(ifa.pxlen); + ifa.prefix = ipa_and(ifa.ip, netmask); + ifa.brd = ipa_or(ifa.ip, ipa_not(netmask)); + if (i->ifa_prefixlen == BITS_PER_IP_ADDRESS - 1) + ifa.opposite = ipa_opposite_m1(ifa.ip); + +#ifndef IPV6 + if (i->ifa_prefixlen == BITS_PER_IP_ADDRESS - 2) + ifa.opposite = ipa_opposite_m2(ifa.ip); + + if ((ifi->flags & IF_BROADCAST) && a[IFA_BROADCAST]) + { + ip_addr xbrd; + memcpy(&xbrd, RTA_DATA(a[IFA_BROADCAST]), sizeof(xbrd)); + ipa_ntoh(xbrd); + if (ipa_equal(xbrd, ifa.prefix) || ipa_equal(xbrd, ifa.brd)) + ifa.brd = xbrd; + else if (ifi->flags & IF_TMP_DOWN) /* Complain only during the first scan */ + log(L_ERR "KIF: Invalid broadcast address %I for %s", xbrd, ifi->name); + } +#endif + } + + scope = ipa_classify(ifa.ip); + if (scope < 0) + { + log(L_ERR "KIF: Invalid interface address %I for %s", ifa.ip, ifi->name); + return; + } + ifa.scope = scope & IADDR_SCOPE_MASK; + + DBG("KIF: IF%d(%s): %s IPA %I, flg %x, net %I/%d, brd %I, opp %I\n", + ifi->index, ifi->name, + new ? "added" : "removed", + ifa.ip, ifa.flags, ifa.prefix, ifa.pxlen, ifa.brd, ifa.opposite); + if (new) + ifa_update(&ifa); + else + ifa_delete(&ifa); +} + +void +kif_do_scan(struct kif_proto *p UNUSED) +{ + struct nlmsghdr *h; + + if_start_update(); + + nl_request_dump(RTM_GETLINK); + while (h = nl_get_scan()) + if (h->nlmsg_type == RTM_NEWLINK || h->nlmsg_type == RTM_DELLINK) + nl_parse_link(h, 1); + else + log(L_DEBUG "nl_scan_ifaces: Unknown packet received (type=%d)", h->nlmsg_type); + + nl_request_dump(RTM_GETADDR); + while (h = nl_get_scan()) + if (h->nlmsg_type == RTM_NEWADDR || h->nlmsg_type == RTM_DELADDR) + nl_parse_addr(h); + else + log(L_DEBUG "nl_scan_ifaces: Unknown packet received (type=%d)", h->nlmsg_type); + + if_end_update(); +} + +/* + * Routes + */ + +static struct krt_proto *nl_table_map[NL_NUM_TABLES]; + +int +krt_capable(rte *e) +{ + rta *a = e->attrs; + + if (a->cast != RTC_UNICAST) + return 0; + + switch (a->dest) + { + case RTD_ROUTER: + case RTD_DEVICE: + if (a->iface == NULL) + return 0; + case RTD_BLACKHOLE: + case RTD_UNREACHABLE: + case RTD_PROHIBIT: + case RTD_MULTIPATH: + break; + default: + return 0; + } + return 1; +} + +static inline int +nh_bufsize(struct mpnh *nh) +{ + int rv = 0; + for (; nh != NULL; nh = nh->next) + rv += RTNH_SIZE; + return rv; +} + +static int +nl_send_route(struct krt_proto *p, rte *e, struct ea_list *eattrs, int new) +{ + eattr *ea; + net *net = e->net; + rta *a = e->attrs; + struct { + struct nlmsghdr h; + struct rtmsg r; + char buf[128 + nh_bufsize(a->nexthops)]; + } r; + + DBG("nl_send_route(%I/%d,new=%d)\n", net->n.prefix, net->n.pxlen, new); + + bzero(&r.h, sizeof(r.h)); + bzero(&r.r, sizeof(r.r)); + r.h.nlmsg_type = new ? RTM_NEWROUTE : RTM_DELROUTE; + r.h.nlmsg_len = NLMSG_LENGTH(sizeof(struct rtmsg)); + r.h.nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK | (new ? NLM_F_CREATE|NLM_F_EXCL : 0); + + r.r.rtm_family = BIRD_AF; + r.r.rtm_dst_len = net->n.pxlen; + r.r.rtm_tos = 0; + r.r.rtm_table = KRT_CF->sys.table_id; + r.r.rtm_protocol = RTPROT_BIRD; + r.r.rtm_scope = RT_SCOPE_UNIVERSE; + nl_add_attr_ipa(&r.h, sizeof(r), RTA_DST, net->n.prefix); + + u32 metric = 0; + if (new && e->attrs->source == RTS_INHERIT) + metric = e->u.krt.metric; + if (ea = ea_find(eattrs, EA_KRT_METRIC)) + metric = ea->u.data; + if (metric != 0) + nl_add_attr_u32(&r.h, sizeof(r), RTA_PRIORITY, metric); + + if (ea = ea_find(eattrs, EA_KRT_PREFSRC)) + nl_add_attr_ipa(&r.h, sizeof(r), RTA_PREFSRC, *(ip_addr *)ea->u.ptr->data); + + if (ea = ea_find(eattrs, EA_KRT_REALM)) + nl_add_attr_u32(&r.h, sizeof(r), RTA_FLOW, ea->u.data); + + /* a->iface != NULL checked in krt_capable() for router and device routes */ + + switch (a->dest) + { + case RTD_ROUTER: + r.r.rtm_type = RTN_UNICAST; + nl_add_attr_u32(&r.h, sizeof(r), RTA_OIF, a->iface->index); + nl_add_attr_ipa(&r.h, sizeof(r), RTA_GATEWAY, a->gw); + break; + case RTD_DEVICE: + r.r.rtm_type = RTN_UNICAST; + nl_add_attr_u32(&r.h, sizeof(r), RTA_OIF, a->iface->index); + break; + case RTD_BLACKHOLE: + r.r.rtm_type = RTN_BLACKHOLE; + break; + case RTD_UNREACHABLE: + r.r.rtm_type = RTN_UNREACHABLE; + break; + case RTD_PROHIBIT: + r.r.rtm_type = RTN_PROHIBIT; + break; + case RTD_MULTIPATH: + r.r.rtm_type = RTN_UNICAST; + nl_add_multipath(&r.h, sizeof(r), a->nexthops); + break; + default: + bug("krt_capable inconsistent with nl_send_route"); + } + + return nl_exchange(&r.h); +} + +void +krt_replace_rte(struct krt_proto *p, net *n, rte *new, rte *old, struct ea_list *eattrs) +{ + int err = 0; + + /* + * NULL for eattr of the old route is a little hack, but we don't + * get proper eattrs for old in rt_notify() anyway. NULL means no + * extended route attributes and therefore matches if the kernel + * route has any of them. + */ + + if (old) + nl_send_route(p, old, NULL, 0); + + if (new) + err = nl_send_route(p, new, eattrs, 1); + + if (err < 0) + n->n.flags |= KRF_SYNC_ERROR; + else + n->n.flags &= ~KRF_SYNC_ERROR; +} + + +#define SKIP(ARG...) do { DBG("KRT: Ignoring route - " ARG); return; } while(0) + +static void +nl_parse_route(struct nlmsghdr *h, int scan) +{ + struct krt_proto *p; + struct rtmsg *i; + struct rtattr *a[RTA_CACHEINFO+1]; + int new = h->nlmsg_type == RTM_NEWROUTE; + + ip_addr dst = IPA_NONE; + u32 oif = ~0; + int src; + + if (!(i = nl_checkin(h, sizeof(*i))) || !nl_parse_attrs(RTM_RTA(i), a, sizeof(a))) + return; + if (i->rtm_family != BIRD_AF) + return; + if ((a[RTA_DST] && RTA_PAYLOAD(a[RTA_DST]) != sizeof(ip_addr)) || +#ifdef IPV6 + (a[RTA_IIF] && RTA_PAYLOAD(a[RTA_IIF]) != 4) || +#endif + (a[RTA_OIF] && RTA_PAYLOAD(a[RTA_OIF]) != 4) || + (a[RTA_GATEWAY] && RTA_PAYLOAD(a[RTA_GATEWAY]) != sizeof(ip_addr)) || + (a[RTA_PRIORITY] && RTA_PAYLOAD(a[RTA_PRIORITY]) != 4) || + (a[RTA_PREFSRC] && RTA_PAYLOAD(a[RTA_PREFSRC]) != sizeof(ip_addr)) || + (a[RTA_FLOW] && RTA_PAYLOAD(a[RTA_OIF]) != 4)) + { + log(L_ERR "KRT: Malformed message received"); + return; + } + + if (a[RTA_DST]) + { + memcpy(&dst, RTA_DATA(a[RTA_DST]), sizeof(dst)); + ipa_ntoh(dst); + } + + if (a[RTA_OIF]) + memcpy(&oif, RTA_DATA(a[RTA_OIF]), sizeof(oif)); + + p = nl_table_map[i->rtm_table]; /* Do we know this table? */ + DBG("KRT: Got %I/%d, type=%d, oif=%d, table=%d, prid=%d, proto=%s\n", dst, i->rtm_dst_len, i->rtm_type, oif, i->rtm_table, i->rtm_protocol, p ? p->p.name : "(none)"); + if (!p) + SKIP("unknown table %d\n", i->rtm_table); + + +#ifdef IPV6 + if (a[RTA_IIF]) + SKIP("IIF set\n"); +#else + if (i->rtm_tos != 0) /* We don't support TOS */ + SKIP("TOS %02x\n", i->rtm_tos); +#endif + + if (scan && !new) + SKIP("RTM_DELROUTE in scan\n"); + + int c = ipa_classify_net(dst); + if ((c < 0) || !(c & IADDR_HOST) || ((c & IADDR_SCOPE_MASK) <= SCOPE_LINK)) + SKIP("strange class/scope\n"); + + // ignore rtm_scope, it is not a real scope + // if (i->rtm_scope != RT_SCOPE_UNIVERSE) + // SKIP("scope %u\n", i->rtm_scope); + + switch (i->rtm_protocol) + { + case RTPROT_UNSPEC: + SKIP("proto unspec\n"); + + case RTPROT_REDIRECT: + src = KRT_SRC_REDIRECT; + break; + + case RTPROT_KERNEL: + src = KRT_SRC_KERNEL; + return; + + case RTPROT_BIRD: + if (!scan) + SKIP("echo\n"); + src = KRT_SRC_BIRD; + break; + + case RTPROT_BOOT: + default: + src = KRT_SRC_ALIEN; + } + + net *net = net_get(p->p.table, dst, i->rtm_dst_len); + + rta ra = { + .proto = &p->p, + .source = RTS_INHERIT, + .scope = SCOPE_UNIVERSE, + .cast = RTC_UNICAST + }; + + switch (i->rtm_type) + { + case RTN_UNICAST: + + if (a[RTA_MULTIPATH]) + { + ra.dest = RTD_MULTIPATH; + ra.nexthops = nl_parse_multipath(p, a[RTA_MULTIPATH]); + if (!ra.nexthops) + { + log(L_ERR "KRT: Received strange multipath route %I/%d", + net->n.prefix, net->n.pxlen); + return; + } + + break; + } + + ra.iface = if_find_by_index(oif); + if (!ra.iface) + { + log(L_ERR "KRT: Received route %I/%d with unknown ifindex %u", + net->n.prefix, net->n.pxlen, oif); + return; + } + + if (a[RTA_GATEWAY]) + { + neighbor *ng; + ra.dest = RTD_ROUTER; + memcpy(&ra.gw, RTA_DATA(a[RTA_GATEWAY]), sizeof(ra.gw)); + ipa_ntoh(ra.gw); + + /* Silently skip strange 6to4 routes */ + if (ipa_in_net(ra.gw, IPA_NONE, 96)) + return; + + ng = neigh_find2(&p->p, &ra.gw, ra.iface, + (i->rtm_flags & RTNH_F_ONLINK) ? NEF_ONLINK : 0); + if (!ng || (ng->scope == SCOPE_HOST)) + { + log(L_ERR "KRT: Received route %I/%d with strange next-hop %I", + net->n.prefix, net->n.pxlen, ra.gw); + return; + } + } + else + { + ra.dest = RTD_DEVICE; + + /* + * In Linux IPv6, 'native' device routes have proto + * RTPROT_BOOT and not RTPROT_KERNEL (which they have in + * IPv4 and which is expected). We cannot distinguish + * 'native' and user defined device routes, so we ignore all + * such device routes and for consistency, we have the same + * behavior in IPv4. Anyway, users should use RTPROT_STATIC + * for their 'alien' routes. + */ + + if (i->rtm_protocol == RTPROT_BOOT) + src = KRT_SRC_KERNEL; + } + + break; + case RTN_BLACKHOLE: + ra.dest = RTD_BLACKHOLE; + break; + case RTN_UNREACHABLE: + ra.dest = RTD_UNREACHABLE; + break; + case RTN_PROHIBIT: + ra.dest = RTD_PROHIBIT; + break; + /* FIXME: What about RTN_THROW? */ + default: + SKIP("type %d\n", i->rtm_type); + return; + } + + rte *e = rte_get_temp(&ra); + e->net = net; + e->u.krt.src = src; + e->u.krt.proto = i->rtm_protocol; + e->u.krt.type = i->rtm_type; + + if (a[RTA_PRIORITY]) + memcpy(&e->u.krt.metric, RTA_DATA(a[RTA_PRIORITY]), sizeof(e->u.krt.metric)); + else + e->u.krt.metric = 0; + + if (a[RTA_PREFSRC]) + { + ip_addr ps; + memcpy(&ps, RTA_DATA(a[RTA_PREFSRC]), sizeof(ps)); + ipa_ntoh(ps); + + ea_list *ea = alloca(sizeof(ea_list) + sizeof(eattr)); + ea->next = ra.eattrs; + ra.eattrs = ea; + ea->flags = EALF_SORTED; + ea->count = 1; + ea->attrs[0].id = EA_KRT_PREFSRC; + ea->attrs[0].flags = 0; + ea->attrs[0].type = EAF_TYPE_IP_ADDRESS; + ea->attrs[0].u.ptr = alloca(sizeof(struct adata) + sizeof(ps)); + ea->attrs[0].u.ptr->length = sizeof(ps); + memcpy(ea->attrs[0].u.ptr->data, &ps, sizeof(ps)); + } + + if (a[RTA_FLOW]) + { + ea_list *ea = alloca(sizeof(ea_list) + sizeof(eattr)); + ea->next = ra.eattrs; + ra.eattrs = ea; + ea->flags = EALF_SORTED; + ea->count = 1; + ea->attrs[0].id = EA_KRT_REALM; + ea->attrs[0].flags = 0; + ea->attrs[0].type = EAF_TYPE_INT; + memcpy(&ea->attrs[0].u.data, RTA_DATA(a[RTA_FLOW]), 4); + } + + if (scan) + krt_got_route(p, e); + else + krt_got_route_async(p, e, new); +} + +void +krt_do_scan(struct krt_proto *p UNUSED) /* CONFIG_ALL_TABLES_AT_ONCE => p is NULL */ +{ + struct nlmsghdr *h; + + nl_request_dump(RTM_GETROUTE); + while (h = nl_get_scan()) + if (h->nlmsg_type == RTM_NEWROUTE || h->nlmsg_type == RTM_DELROUTE) + nl_parse_route(h, 1); + else + log(L_DEBUG "nl_scan_fire: Unknown packet received (type=%d)", h->nlmsg_type); +} + +/* + * Asynchronous Netlink interface + */ + +static sock *nl_async_sk; /* BIRD socket for asynchronous notifications */ +static byte *nl_async_rx_buffer; /* Receive buffer */ + +static void +nl_async_msg(struct nlmsghdr *h) +{ + switch (h->nlmsg_type) + { + case RTM_NEWROUTE: + case RTM_DELROUTE: + DBG("KRT: Received async route notification (%d)\n", h->nlmsg_type); + nl_parse_route(h, 0); + break; + case RTM_NEWLINK: + case RTM_DELLINK: + DBG("KRT: Received async link notification (%d)\n", h->nlmsg_type); + nl_parse_link(h, 0); + break; + case RTM_NEWADDR: + case RTM_DELADDR: + DBG("KRT: Received async address notification (%d)\n", h->nlmsg_type); + nl_parse_addr(h); + break; + default: + DBG("KRT: Received unknown async notification (%d)\n", h->nlmsg_type); + } +} + +static int +nl_async_hook(sock *sk, int size UNUSED) +{ + struct iovec iov = { nl_async_rx_buffer, NL_RX_SIZE }; + struct sockaddr_nl sa; + struct msghdr m = { (struct sockaddr *) &sa, sizeof(sa), &iov, 1, NULL, 0, 0 }; + struct nlmsghdr *h; + int x; + unsigned int len; + + x = recvmsg(sk->fd, &m, 0); + if (x < 0) + { + if (errno == ENOBUFS) + { + /* + * Netlink reports some packets have been thrown away. + * One day we might react to it by asking for route table + * scan in near future. + */ + return 1; /* More data are likely to be ready */ + } + else if (errno != EWOULDBLOCK) + log(L_ERR "Netlink recvmsg: %m"); + return 0; + } + if (sa.nl_pid) /* It isn't from the kernel */ + { + DBG("Non-kernel packet\n"); + return 1; + } + h = (void *) nl_async_rx_buffer; + len = x; + if (m.msg_flags & MSG_TRUNC) + { + log(L_WARN "Netlink got truncated asynchronous message"); + return 1; + } + while (NLMSG_OK(h, len)) + { + nl_async_msg(h); + h = NLMSG_NEXT(h, len); + } + if (len) + log(L_WARN "nl_async_hook: Found packet remnant of size %d", len); + return 1; +} + +static void +nl_open_async(void) +{ + sock *sk; + struct sockaddr_nl sa; + int fd; + static int nl_open_tried = 0; + + if (nl_open_tried) + return; + nl_open_tried = 1; + + DBG("KRT: Opening async netlink socket\n"); + + fd = socket(PF_NETLINK, SOCK_RAW, NETLINK_ROUTE); + if (fd < 0) + { + log(L_ERR "Unable to open asynchronous rtnetlink socket: %m"); + return; + } + + bzero(&sa, sizeof(sa)); + sa.nl_family = AF_NETLINK; +#ifdef IPV6 + sa.nl_groups = RTMGRP_LINK | RTMGRP_IPV6_IFADDR | RTMGRP_IPV6_ROUTE; +#else + sa.nl_groups = RTMGRP_LINK | RTMGRP_IPV4_IFADDR | RTMGRP_IPV4_ROUTE; +#endif + if (bind(fd, (struct sockaddr *) &sa, sizeof(sa)) < 0) + { + log(L_ERR "Unable to bind asynchronous rtnetlink socket: %m"); + return; + } + + sk = nl_async_sk = sk_new(krt_pool); + sk->type = SK_MAGIC; + sk->rx_hook = nl_async_hook; + sk->fd = fd; + if (sk_open(sk)) + bug("Netlink: sk_open failed"); + + if (!nl_async_rx_buffer) + nl_async_rx_buffer = xmalloc(NL_RX_SIZE); +} + +/* + * Interface to the UNIX krt module + */ + +static u8 nl_cf_table[(NL_NUM_TABLES+7) / 8]; + +void +krt_sys_start(struct krt_proto *p, int first) +{ + nl_table_map[KRT_CF->sys.table_id] = p; + if (first) + { + nl_open(); + nl_open_async(); + } +} + +void +krt_sys_shutdown(struct krt_proto *p UNUSED, int last UNUSED) +{ +} + +int +krt_sys_reconfigure(struct krt_proto *p UNUSED, struct krt_config *n, struct krt_config *o) +{ + return n->sys.table_id == o->sys.table_id; +} + + +void +krt_sys_preconfig(struct config *c UNUSED) +{ + bzero(&nl_cf_table, sizeof(nl_cf_table)); +} + +void +krt_sys_postconfig(struct krt_config *x) +{ + int id = x->sys.table_id; + + if (nl_cf_table[id/8] & (1 << (id%8))) + cf_error("Multiple kernel syncers defined for table #%d", id); + nl_cf_table[id/8] |= (1 << (id%8)); +} + +void +krt_sys_init_config(struct krt_config *cf) +{ + cf->sys.table_id = RT_TABLE_MAIN; +} + +void +krt_sys_copy_config(struct krt_config *d, struct krt_config *s) +{ + d->sys.table_id = s->sys.table_id; +} + + + +void +kif_sys_start(struct kif_proto *p UNUSED) +{ + nl_open(); + nl_open_async(); +} + +void +kif_sys_shutdown(struct kif_proto *p UNUSED) +{ +} |