BGP: Use reallocation for capability structure
Instead of having large stack buffer for max amount of AFI/SAFI pairs. The old code is not correct w.r.t. extendeded option length, as more AFI/SAFI pairs may fit into the capability option.
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parent
524d253853
commit
4fa0e472cf
2 changed files with 30 additions and 16 deletions
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@ -29,4 +29,6 @@ static inline u32 u32_hash(u32 v) { return v * 2902958171u; }
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static inline u8 u32_popcount(u32 v) { return __builtin_popcount(v); }
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static inline int uint_is_pow2(uint n) { return n && !(n & (n-1)); }
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#endif
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@ -185,14 +185,20 @@ bgp_find_af_caps(struct bgp_caps *caps, u32 afi)
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}
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static struct bgp_af_caps *
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bgp_get_af_caps(struct bgp_caps *caps, u32 afi)
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bgp_get_af_caps(struct bgp_caps **pcaps, u32 afi)
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{
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struct bgp_caps *caps = *pcaps;
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struct bgp_af_caps *ac;
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WALK_AF_CAPS(caps, ac)
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if (ac->afi == afi)
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return ac;
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uint n = caps->af_count;
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if (uint_is_pow2(n))
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*pcaps = caps = mb_realloc(caps, sizeof(struct bgp_caps) +
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(2 * n) * sizeof(struct bgp_af_caps));
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ac = &caps->af_data[caps->af_count++];
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memset(ac, 0, sizeof(struct bgp_af_caps));
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ac->afi = afi;
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@ -412,13 +418,22 @@ bgp_write_capabilities(struct bgp_conn *conn, byte *buf)
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}
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static int
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bgp_read_capabilities(struct bgp_conn *conn, struct bgp_caps *caps, byte *pos, int len)
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bgp_read_capabilities(struct bgp_conn *conn, byte *pos, int len)
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{
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struct bgp_proto *p = conn->bgp;
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struct bgp_caps *caps;
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struct bgp_af_caps *ac;
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int i, cl;
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u32 af;
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if (!conn->remote_caps)
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caps = mb_allocz(p->p.pool, sizeof(struct bgp_caps) + sizeof(struct bgp_af_caps));
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else
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{
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caps = conn->remote_caps;
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conn->remote_caps = NULL;
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}
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caps->length += len;
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while (len > 0)
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@ -437,7 +452,7 @@ bgp_read_capabilities(struct bgp_conn *conn, struct bgp_caps *caps, byte *pos, i
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goto err;
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af = get_af4(pos+2);
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ac = bgp_get_af_caps(caps, af);
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ac = bgp_get_af_caps(&caps, af);
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ac->ready = 1;
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break;
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@ -460,7 +475,7 @@ bgp_read_capabilities(struct bgp_conn *conn, struct bgp_caps *caps, byte *pos, i
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continue;
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af = get_af4(pos+2+i);
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ac = bgp_get_af_caps(caps, af);
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ac = bgp_get_af_caps(&caps, af);
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ac->ext_next_hop = 1;
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}
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break;
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@ -490,7 +505,7 @@ bgp_read_capabilities(struct bgp_conn *conn, struct bgp_caps *caps, byte *pos, i
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for (i = 2; i < cl; i += 4)
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{
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af = get_af3(pos+2+i);
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ac = bgp_get_af_caps(caps, af);
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ac = bgp_get_af_caps(&caps, af);
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ac->gr_able = 1;
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ac->gr_af_flags = pos[2+i+3];
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}
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@ -522,7 +537,7 @@ bgp_read_capabilities(struct bgp_conn *conn, struct bgp_caps *caps, byte *pos, i
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for (i = 0; i < cl; i += 4)
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{
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af = get_af3(pos+2+i);
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ac = bgp_get_af_caps(caps, af);
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ac = bgp_get_af_caps(&caps, af);
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ac->add_path = pos[2+i+3];
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}
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break;
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@ -551,7 +566,7 @@ bgp_read_capabilities(struct bgp_conn *conn, struct bgp_caps *caps, byte *pos, i
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for (i = 0; i < cl; i += 7)
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{
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af = get_af3(pos+2+i);
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ac = bgp_get_af_caps(caps, af);
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ac = bgp_get_af_caps(&caps, af);
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ac->llgr_able = 1;
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ac->llgr_flags = pos[2+i+3];
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ac->llgr_time = get_u24(pos + 2+i+4);
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@ -577,9 +592,11 @@ bgp_read_capabilities(struct bgp_conn *conn, struct bgp_caps *caps, byte *pos, i
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}
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}
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conn->remote_caps = caps;
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return 0;
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err:
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mb_free(caps);
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bgp_error(conn, 2, 0, NULL, 0);
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return -1;
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}
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@ -624,7 +641,6 @@ static int
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bgp_read_options(struct bgp_conn *conn, byte *pos, uint len, uint rest)
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{
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struct bgp_proto *p = conn->bgp;
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struct bgp_caps *caps;
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int ext = 0;
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/* Handle extended length (draft-ietf-idr-ext-opt-param-07) */
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@ -644,10 +660,6 @@ bgp_read_options(struct bgp_conn *conn, byte *pos, uint len, uint rest)
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if (len > rest)
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goto err;
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/* Max number of announced AFIs is limited by max option length (255) */
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caps = alloca(sizeof(struct bgp_caps) + 64 * sizeof(struct bgp_af_caps));
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memset(caps, 0, sizeof(struct bgp_caps));
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/* Length of option parameter header */
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uint hlen = ext ? 3 : 2;
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@ -666,7 +678,7 @@ bgp_read_options(struct bgp_conn *conn, byte *pos, uint len, uint rest)
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{
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/* BGP capabilities, RFC 5492 */
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if (p->cf->capabilities)
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if (bgp_read_capabilities(conn, caps, pos + hlen, olen) < 0)
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if (bgp_read_capabilities(conn, pos + hlen, olen) < 0)
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return -1;
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}
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else
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@ -679,9 +691,9 @@ bgp_read_options(struct bgp_conn *conn, byte *pos, uint len, uint rest)
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ADVANCE(pos, len, hlen + olen);
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}
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uint n = sizeof(struct bgp_caps) + caps->af_count * sizeof(struct bgp_af_caps);
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conn->remote_caps = mb_allocz(p->p.pool, n);
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memcpy(conn->remote_caps, caps, n);
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/* Prepare empty caps if no capability option was announced */
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if (!conn->remote_caps)
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conn->remote_caps = mb_allocz(p->p.pool, sizeof(struct bgp_caps));
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return 0;
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