diff options
Diffstat (limited to 'proto/bgp/packets.c')
| -rw-r--r-- | proto/bgp/packets.c | 158 |
1 files changed, 120 insertions, 38 deletions
diff --git a/proto/bgp/packets.c b/proto/bgp/packets.c index 2e6f0b6..c18c6e4 100644 --- a/proto/bgp/packets.c +++ b/proto/bgp/packets.c @@ -12,6 +12,7 @@ #include "nest/iface.h" #include "nest/protocol.h" #include "nest/route.h" +#include "nest/attrs.h" #include "conf/conf.h" #include "lib/unaligned.h" #include "lib/socket.h" @@ -30,33 +31,64 @@ bgp_create_notification(struct bgp_conn *conn, byte *buf) return buf + 2 + conn->notify_size; } +#ifdef IPV6 +static byte * +bgp_put_cap_ipv6(struct bgp_conn *conn UNUSED, byte *buf) +{ + *buf++ = 1; /* Capability 1: Multiprotocol extensions */ + *buf++ = 4; /* Capability data length */ + *buf++ = 0; /* We support AF IPv6 */ + *buf++ = BGP_AF_IPV6; + *buf++ = 0; /* RFU */ + *buf++ = 1; /* and SAFI 1 */ + return buf; +} +#endif + +static byte * +bgp_put_cap_as4(struct bgp_conn *conn, byte *buf) +{ + *buf++ = 65; /* Capability 65: Support for 4-octet AS number */ + *buf++ = 4; /* Capability data length */ + put_u32(buf, conn->bgp->local_as); + return buf + 4; +} + static byte * bgp_create_open(struct bgp_conn *conn, byte *buf) { struct bgp_proto *p = conn->bgp; + byte *cap; + int cap_len; BGP_TRACE(D_PACKETS, "Sending OPEN(ver=%d,as=%d,hold=%d,id=%08x)", BGP_VERSION, p->local_as, p->cf->hold_time, p->local_id); buf[0] = BGP_VERSION; - put_u16(buf+1, p->local_as); + put_u16(buf+1, (p->local_as < 0xFFFF) ? p->local_as : AS_TRANS); put_u16(buf+3, p->cf->hold_time); put_u32(buf+5, p->local_id); -#ifndef IPV6 - buf[9] = 0; /* No optional parameters */ - return buf+10; -#else - buf += 9; - *buf++ = 8; /* Optional params len */ - *buf++ = 2; /* Option: Capability list */ - *buf++ = 6; /* Option length */ - *buf++ = 1; /* Capability 1: Multiprotocol extensions */ - *buf++ = 4; /* Capability data length */ - *buf++ = 0; /* We support AF IPv6 */ - *buf++ = BGP_AF_IPV6; - *buf++ = 0; /* RFU */ - *buf++ = 1; /* and SAFI 1 */ - return buf; + /* Skipped 3 B for length field and Capabilities parameter header */ + cap = buf + 12; + +#ifdef IPV6 + cap = bgp_put_cap_ipv6(conn, cap); #endif + if (p->cf->enable_as4) + cap = bgp_put_cap_as4(conn, cap); + + cap_len = cap - buf - 12; + if (cap_len > 0) + { + buf[9] = cap_len + 2; /* Optional params len */ + buf[10] = 2; /* Option: Capability list */ + buf[11] = cap_len; /* Option length */ + return cap; + } + else + { + buf[9] = 0; /* No optional parameters */ + return buf + 10; + } } static unsigned int @@ -118,7 +150,7 @@ bgp_create_update(struct bgp_conn *conn, byte *buf) continue; } DBG("Processing bucket %p\n", buck); - a_size = bgp_encode_attrs(w+2, buck->eattrs, 1024); + a_size = bgp_encode_attrs(p, w+2, buck->eattrs, 1024); put_u16(w, a_size); w += a_size + 2; r_size = bgp_encode_prefixes(p, w, buck, remains - a_size); @@ -161,12 +193,12 @@ bgp_create_update(struct bgp_conn *conn, byte *buf) if ((buck = p->withdraw_bucket) && !EMPTY_LIST(buck->prefixes)) { DBG("Withdrawn routes:\n"); - tmp = bgp_attach_attr(&ea, bgp_linpool, BA_MP_UNREACH_NLRI, remains-8); + tmp = bgp_attach_attr_wa(&ea, bgp_linpool, BA_MP_UNREACH_NLRI, remains-8); *tmp++ = 0; *tmp++ = BGP_AF_IPV6; *tmp++ = 1; ea->attrs[0].u.ptr->length = bgp_encode_prefixes(p, tmp, buck, remains-11); - size = bgp_encode_attrs(w, ea, remains); + size = bgp_encode_attrs(p, w, ea, remains); w += size; remains -= size; } @@ -183,10 +215,10 @@ bgp_create_update(struct bgp_conn *conn, byte *buf) continue; } DBG("Processing bucket %p\n", buck); - size = bgp_encode_attrs(w, buck->eattrs, 1024); + size = bgp_encode_attrs(p, w, buck->eattrs, 1024); w += size; remains -= size; - tstart = tmp = bgp_attach_attr(&ea, bgp_linpool, BA_MP_REACH_NLRI, remains-8); + tstart = tmp = bgp_attach_attr_wa(&ea, bgp_linpool, BA_MP_REACH_NLRI, remains-8); *tmp++ = 0; *tmp++ = BGP_AF_IPV6; *tmp++ = 1; @@ -230,7 +262,7 @@ bgp_create_update(struct bgp_conn *conn, byte *buf) *tmp++ = 0; /* No SNPA information */ tmp += bgp_encode_prefixes(p, tmp, buck, remains - (8+3+32+1)); ea->attrs[0].u.ptr->length = tmp - tstart; - w += bgp_encode_attrs(w, ea, remains); + w += bgp_encode_attrs(p, w, ea, remains); break; } } @@ -353,9 +385,50 @@ bgp_tx(sock *sk) ; } +/* Capatibility negotiation as per RFC 2842 */ + +void +bgp_parse_capabilities(struct bgp_conn *conn, byte *opt, int len) +{ + struct bgp_proto *p = conn->bgp; + int cl; + u32 as; + + while (len > 0) + { + if (len < 2 || len < 2 + opt[1]) + goto err; + + cl = opt[1]; + + switch (opt[0]) + { + case 65: + if (cl != 4) + goto err; + p->as4_support = 1; + p->as4_session = p->cf->enable_as4; + if (p->as4_session) + conn->advertised_as = get_u32(opt + 2); + break; + + /* We can safely ignore all other capabilities */ + } + len -= 2 + cl; + opt += 2 + cl; + } + return; + + err: + bgp_error(conn, 2, 0, NULL, 0); + return; +} + static int bgp_parse_options(struct bgp_conn *conn, byte *opt, int len) { + int ol; + while (len > 0) { if (len < 2 || len < 2 + opt[1]) @@ -369,12 +442,14 @@ bgp_parse_options(struct bgp_conn *conn, byte *opt, int len) DBG("\n"); } #endif + + ol = opt[1]; switch (opt[0]) { case 2: - /* Capatibility negotiation as per RFC 2842 */ - /* We can safely ignore all capabilities announced */ + bgp_parse_capabilities(conn, opt + 2, ol); break; + default: /* * BGP specs don't tell us to send which option @@ -382,11 +457,11 @@ bgp_parse_options(struct bgp_conn *conn, byte *opt, int len) * to do so. Also, capability negotiation with * Cisco routers doesn't work without that. */ - bgp_error(conn, 2, 4, opt, opt[1]); + bgp_error(conn, 2, 4, opt, ol); return 0; } - len -= 2 + opt[1]; - opt += 2 + opt[1]; + len -= 2 + ol; + opt += 2 + ol; } return 0; } @@ -397,7 +472,7 @@ bgp_rx_open(struct bgp_conn *conn, byte *pkt, int len) struct bgp_conn *other; struct bgp_proto *p = conn->bgp; struct bgp_config *cf = p->cf; - unsigned as, hold; + unsigned hold; u32 id; /* Check state */ @@ -409,20 +484,27 @@ bgp_rx_open(struct bgp_conn *conn, byte *pkt, int len) { bgp_error(conn, 1, 2, pkt+16, 2); return; } if (pkt[19] != BGP_VERSION) { bgp_error(conn, 2, 1, pkt+19, 1); return; } /* RFC 1771 says 16 bits, draft-09 tells to use 8 */ - as = get_u16(pkt+20); + conn->advertised_as = get_u16(pkt+20); hold = get_u16(pkt+22); id = get_u32(pkt+24); - BGP_TRACE(D_PACKETS, "Got OPEN(as=%d,hold=%d,id=%08x)", as, hold, id); - if (cf->remote_as && as != p->remote_as) - { bgp_error(conn, 2, 2, pkt+20, -2); return; } - if (hold > 0 && hold < 3) - { bgp_error(conn, 2, 6, pkt+22, 2); return; } - p->remote_id = id; + BGP_TRACE(D_PACKETS, "Got OPEN(as=%d,hold=%d,id=%08x)", conn->advertised_as, hold, id); + + p->remote_id = id; // ??? if (bgp_parse_options(conn, pkt+29, pkt[28])) return; + + if (hold > 0 && hold < 3) + { bgp_error(conn, 2, 6, pkt+22, 2); return; } + if (!id || id == 0xffffffff || id == p->local_id) { bgp_error(conn, 2, 3, pkt+24, -4); return; } + + if (conn->advertised_as != p->remote_as) + { + bgp_error(conn, 2, 2, (byte *) &(conn->advertised_as), -4); return; + } + /* Check the other connection */ other = (conn == &p->outgoing_conn) ? &p->incoming_conn : &p->outgoing_conn; switch (other->state) @@ -463,7 +545,7 @@ bgp_rx_open(struct bgp_conn *conn, byte *pkt, int len) else conn->hold_time = p->cf->hold_time; conn->keepalive_time = p->cf->keepalive_time ? : conn->hold_time / 3; - p->remote_as = as; + // p->remote_as = conn->advertised_as; p->remote_id = id; DBG("BGP: Hold timer set to %d, keepalive to %d, AS to %d, ID to %x\n", conn->hold_time, conn->keepalive_time, p->remote_as, p->remote_id); @@ -621,7 +703,7 @@ bgp_do_rx_update(struct bgp_conn *conn, /* Create fake NEXT_HOP attribute */ if (len < 1 || (*x != 16 && *x != 32) || len < *x + 2) goto bad; - memcpy(bgp_attach_attr(&a0->eattrs, bgp_linpool, BA_NEXT_HOP, 16), x+1, 16); + bgp_attach_attr_ip(&a0->eattrs, bgp_linpool, BA_NEXT_HOP, x[1]); len -= *x + 2; x += *x + 1; @@ -720,7 +802,7 @@ static struct { { 2, 4, "Unsupported optional parameter" }, { 2, 5, "Authentication failure" }, { 2, 6, "Unacceptable hold time" }, - { 2, 7, "Required capability missing" }, /* capability negotiation draft */ + { 2, 7, "Required capability missing" }, /* [RFC3392] */ { 3, 0, "Invalid UPDATE message" }, { 3, 1, "Malformed attribute list" }, { 3, 2, "Unrecognized well-known attribute" }, |