diff options
Diffstat (limited to 'proto/ospf/lsalib.c')
| -rw-r--r-- | proto/ospf/lsalib.c | 149 |
1 files changed, 23 insertions, 126 deletions
diff --git a/proto/ospf/lsalib.c b/proto/ospf/lsalib.c index ce6fb178..66a3a23d 100644 --- a/proto/ospf/lsalib.c +++ b/proto/ospf/lsalib.c @@ -2,14 +2,15 @@ * BIRD -- OSPF * * (c) 1999--2004 Ondrej Filip <feela@network.cz> - * (c) 2009--2014 Ondrej Zajicek <santiago@crfreenet.org> - * (c) 2009--2014 CZ.NIC z.s.p.o. + * (c) 2009--2015 Ondrej Zajicek <santiago@crfreenet.org> + * (c) 2009--2015 CZ.NIC z.s.p.o. * * Can be freely distributed and used under the terms of the GNU GPL. */ #include "ospf.h" +#include "lib/fletcher16.h" #ifndef CPU_BIG_ENDIAN void @@ -150,145 +151,41 @@ lsa_get_type_domain_(u32 itype, struct ospf_iface *ifa, u32 *otype, u32 *domain) } - -/* void -buf_dump(const char *hdr, const byte *buf, int blen) +lsa_generate_checksum(struct ospf_lsa_header *lsa, const u8 *body) { - char b2[1024]; - char *bp; - int first = 1; - int i; - - const char *lhdr = hdr; - - bp = b2; - for(i = 0; i < blen; i++) - { - if ((i > 0) && ((i % 16) == 0)) - { - *bp = 0; - log(L_WARN "%s\t%s", lhdr, b2); - lhdr = ""; - bp = b2; - } - - bp += snprintf(bp, 1022, "%02x ", buf[i]); - - } - - *bp = 0; - log(L_WARN "%s\t%s", lhdr, b2); -} -*/ - -#define MODX 4102 /* larges signed value without overflow */ - -/* Fletcher Checksum -- Refer to RFC1008. */ -#define MODX 4102 -#define LSA_CHECKSUM_OFFSET 15 - -/* FIXME This is VERY uneficient, I have huge endianity problems */ -void -lsasum_calculate(struct ospf_lsa_header *h, void *body) -{ - u16 length = h->length; - - // log(L_WARN "Checksum %R %R %d start (len %d)", h->id, h->rt, h->type, length); - lsa_hton_hdr(h, h); - lsa_hton_body1(body, length - sizeof(struct ospf_lsa_header)); + struct fletcher16_context ctx; + struct ospf_lsa_header hdr; + u16 len = lsa->length; /* - char buf[1024]; - memcpy(buf, h, sizeof(struct ospf_lsa_header)); - memcpy(buf + sizeof(struct ospf_lsa_header), body, length - sizeof(struct ospf_lsa_header)); - buf_dump("CALC", buf, length); - */ + * lsa and body are in the host order, we need to compute Fletcher-16 checksum + * for data in the network order. We also skip the initial age field. + */ - (void) lsasum_check(h, body, 1); + lsa_hton_hdr(lsa, &hdr); + hdr.checksum = 0; - // log(L_WARN "Checksum result %4x", h->checksum); - - lsa_ntoh_hdr(h, h); - lsa_ntoh_body1(body, length - sizeof(struct ospf_lsa_header)); + fletcher16_init(&ctx); + fletcher16_update(&ctx, (u8 *) &hdr + 2, sizeof(struct ospf_lsa_header) - 2); + fletcher16_update_n32(&ctx, body, len - sizeof(struct ospf_lsa_header)); + lsa->checksum = fletcher16_final(&ctx, len, OFFSETOF(struct ospf_lsa_header, checksum)); } -/* - * Calculates the Fletcher checksum of an OSPF LSA. - * - * If 'update' is non-zero, the checkbytes (X and Y in RFC905) are calculated - * and the checksum field in the header is updated. The return value is the - * checksum as placed in the header (in network byte order). - * - * If 'update' is zero, only C0 and C1 are calculated and the header is kept - * intact. The return value is a combination of C0 and C1; if the return value - * is exactly zero the checksum is considered valid, any non-zero value is - * invalid. - * - * Note that this function expects the input LSA to be in network byte order. - */ u16 -lsasum_check(struct ospf_lsa_header *h, void *body, int update) +lsa_verify_checksum(const void *lsa_n, int lsa_len) { - u8 *sp, *ep, *p, *q, *b; - int c0 = 0, c1 = 0; - int x, y; - u16 length; - - b = body; - sp = (char *) h; - sp += 2; /* Skip Age field */ - length = ntohs(h->length) - 2; - if (update) h->checksum = 0; - - for (ep = sp + length; sp < ep; sp = q) - { /* Actually MODX is very large, do we need the for-cyclus? */ - q = sp + MODX; - if (q > ep) - q = ep; - for (p = sp; p < q; p++) - { - /* - * I count with bytes from header and than from body - * but if there is no body, it's appended to header - * (probably checksum in update receiving) and I go on - * after header - */ - if ((b == NULL) || (p < (u8 *) (h + 1))) - { - c0 += *p; - } - else - { - c0 += *(b + (p - (u8 *) (h + 1))); - } - - c1 += c0; - } - c0 %= 255; - c1 %= 255; - } + struct fletcher16_context ctx; - if (!update) { - /* - * When testing the checksum, we don't need to calculate x and y. The - * checksum passes if c0 and c1 are both 0. - */ - return (c0 << 8) | (c1 & 0xff); - } + /* The whole LSA is at lsa_n in net order, we just skip initial age field */ - x = (int)((length - LSA_CHECKSUM_OFFSET) * c0 - c1) % 255; - if (x <= 0) - x += 255; - y = 510 - c0 - x; - if (y > 255) - y -= 255; + fletcher16_init(&ctx); + fletcher16_update(&ctx, (u8 *) lsa_n + 2, lsa_len - 2); - ((u8 *) & h->checksum)[0] = x; - ((u8 *) & h->checksum)[1] = y; - return h->checksum; + return fletcher16_compute(&ctx) == 0; } + int lsa_comp(struct ospf_lsa_header *l1, struct ospf_lsa_header *l2) /* Return codes from point of view of l1 */ |