296 lines
7.2 KiB
C
296 lines
7.2 KiB
C
/*
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* BIRD -- BGP Packet Processing
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*
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* (c) 2000 Martin Mares <mj@ucw.cz>
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*
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* Can be freely distributed and used under the terms of the GNU GPL.
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*/
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#define LOCAL_DEBUG
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#include "nest/bird.h"
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#include "nest/iface.h"
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#include "nest/protocol.h"
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#include "nest/route.h"
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#include "conf/conf.h"
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#include "lib/unaligned.h"
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#include "lib/socket.h"
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#include "bgp.h"
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static byte *
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bgp_create_notification(struct bgp_conn *conn, byte *buf)
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{
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DBG("BGP: Sending notification: code=%d, sub=%d, arg=%d:%d\n", conn->notify_code, conn->notify_subcode, conn->notify_arg, conn->notify_arg_size);
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buf[0] = conn->notify_code;
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buf[1] = conn->notify_subcode;
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switch (conn->notify_arg_size)
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{
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case 1:
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buf[2] = conn->notify_arg; return buf+3;
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case 2:
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put_u16(buf+2, conn->notify_arg); return buf+4;
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case 4:
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put_u32(buf+2, conn->notify_arg); return buf+6;
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default:
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bug("bgp_create_notification: unknown error code size");
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}
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}
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static byte *
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bgp_create_open(struct bgp_conn *conn, byte *buf)
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{
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DBG("BGP: Sending open\n");
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buf[0] = BGP_VERSION;
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put_u16(buf+1, conn->bgp->local_as);
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put_u16(buf+3, conn->bgp->cf->hold_time);
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put_u32(buf+5, conn->bgp->local_id);
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buf[9] = 0; /* No optional parameters */
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return buf+10;
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}
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static byte *
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bgp_create_update(struct bgp_conn *conn, byte *buf)
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{
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DBG("BGP: Sending update\n");
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bug("Don't know how to create updates");
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}
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static void
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bgp_create_header(byte *buf, unsigned int len, unsigned int type)
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{
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memset(buf, 0xff, 16); /* Marker */
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put_u16(buf+16, len);
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buf[18] = type;
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}
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static int
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bgp_fire_tx(struct bgp_conn *conn)
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{
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unsigned int s = conn->packets_to_send;
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sock *sk = conn->sk;
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byte *buf = sk->tbuf;
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byte *pkt = buf + BGP_HEADER_LENGTH;
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byte *end;
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int type;
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if (s & (1 << PKT_SCHEDULE_CLOSE))
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{
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bgp_close_conn(conn);
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return 0;
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}
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if (s & (1 << PKT_NOTIFICATION))
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{
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s = 1 << PKT_SCHEDULE_CLOSE;
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type = PKT_NOTIFICATION;
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end = bgp_create_notification(conn, pkt);
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}
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else if (s & (1 << PKT_KEEPALIVE))
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{
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s &= ~(1 << PKT_KEEPALIVE);
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type = PKT_KEEPALIVE;
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end = pkt; /* Keepalives carry no data */
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DBG("BGP: Sending keepalive\n");
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bgp_start_timer(conn->keepalive_timer, conn->keepalive_time);
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}
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else if (s & (1 << PKT_OPEN))
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{
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s &= ~(1 << PKT_OPEN);
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type = PKT_OPEN;
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end = bgp_create_open(conn, pkt);
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}
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else if (s & (1 << PKT_UPDATE))
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{
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end = bgp_create_update(conn, pkt);
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type = PKT_UPDATE;
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if (!end)
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{
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conn->packets_to_send = 0;
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return 0;
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}
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}
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else
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return 0;
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conn->packets_to_send = s;
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bgp_create_header(buf, end - buf, type);
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return sk_send(sk, end - buf);
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}
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void
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bgp_schedule_packet(struct bgp_conn *conn, int type)
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{
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DBG("BGP: Scheduling packet type %d\n", type);
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conn->packets_to_send |= 1 << type;
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if (conn->sk->tpos == conn->sk->tbuf)
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while (bgp_fire_tx(conn))
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;
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}
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void
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bgp_tx(sock *sk)
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{
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struct bgp_conn *conn = sk->data;
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DBG("BGP: TX hook\n");
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while (bgp_fire_tx(conn))
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;
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}
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static void
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bgp_rx_open(struct bgp_conn *conn, byte *pkt, int len)
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{
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struct bgp_proto *p = conn->bgp;
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struct bgp_config *cf = p->cf;
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unsigned as, hold;
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u32 id;
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/* Check state */
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if (conn->state != BS_OPENSENT)
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{ bgp_error(conn, 5, 0, conn->state, 0); }
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/* Check message contents */
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if (len < 29 || len != 29 + pkt[28])
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{ bgp_error(conn, 1, 2, len, 2); return; }
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if (pkt[19] != BGP_VERSION)
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{ bgp_error(conn, 2, 1, pkt[19], 2); return; }
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as = get_u16(pkt+20);
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hold = get_u16(pkt+22);
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id = get_u32(pkt+24);
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DBG("BGP: OPEN as=%d hold=%d id=%08x\n", as, hold, id);
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if (cf->remote_as && as != p->remote_as)
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{ bgp_error(conn, 2, 2, as, 0); return; }
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if (hold > 0 && hold < 3)
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{ bgp_error(conn, 2, 6, hold, 0); return; }
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p->remote_id = id;
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if (pkt[28]) /* Currently we support no optional parameters */
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{ bgp_error(conn, 2, 4, pkt[28], 0); return; }
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if (!id || id == 0xffffffff || id == p->local_id)
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{ bgp_error(conn, 2, 3, id, 0); return; }
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/* FIXME: What to do with the other connection??? */
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ASSERT(conn == &p->conn);
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/* Update our local variables */
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if (hold < p->cf->hold_time)
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conn->hold_time = hold;
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else
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conn->hold_time = p->cf->hold_time;
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conn->keepalive_time = p->cf->keepalive_time ? : conn->hold_time / 3;
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p->remote_as = as;
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p->remote_id = id;
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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);
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bgp_schedule_packet(conn, PKT_KEEPALIVE);
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bgp_start_timer(conn->hold_timer, conn->hold_time);
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conn->state = BS_OPENCONFIRM;
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}
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static void
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bgp_rx_update(struct bgp_conn *conn, byte *pkt, int len)
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{
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if (conn->state != BS_ESTABLISHED)
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{ bgp_error(conn, 5, 0, conn->state, 0); return; }
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bgp_start_timer(conn->hold_timer, conn->hold_time);
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DBG("BGP: UPDATE (ignored)\n");
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}
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static void
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bgp_rx_notification(struct bgp_conn *conn, byte *pkt, int len)
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{
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unsigned arg;
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if (len < 21)
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{
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bgp_error(conn, 1, 2, len, 2);
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return;
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}
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switch (len)
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{
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case 21: arg = 0; break;
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case 22: arg = pkt[21]; break;
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case 23: arg = get_u16(pkt+21); break;
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case 25: arg = get_u32(pkt+23); break;
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default: DBG("BGP: NOTIFICATION with too much data\n"); /* FIXME */ arg = 0;
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}
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DBG("BGP: NOTIFICATION %d.%d %08x\n", pkt[19], pkt[20], arg); /* FIXME: Better reporting */
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conn->error_flag = 1;
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proto_notify_state(&conn->bgp->p, PS_STOP);
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bgp_schedule_packet(conn, PKT_SCHEDULE_CLOSE);
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}
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static void
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bgp_rx_keepalive(struct bgp_conn *conn, byte *pkt, unsigned len)
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{
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DBG("BGP: KEEPALIVE\n");
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bgp_start_timer(conn->hold_timer, conn->hold_time);
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switch (conn->state)
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{
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case BS_OPENCONFIRM:
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DBG("BGP: UP!!!\n");
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conn->state = BS_ESTABLISHED;
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proto_notify_state(&conn->bgp->p, PS_UP);
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break;
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case BS_ESTABLISHED:
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break;
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default:
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bgp_error(conn, 5, 0, conn->state, 0);
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}
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}
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static void
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bgp_rx_packet(struct bgp_conn *conn, byte *pkt, unsigned len)
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{
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DBG("BGP: Got packet %02x (%d bytes)\n", pkt[18], len);
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switch (pkt[18])
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{
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case PKT_OPEN: return bgp_rx_open(conn, pkt, len);
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case PKT_UPDATE: return bgp_rx_update(conn, pkt, len);
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case PKT_NOTIFICATION: return bgp_rx_notification(conn, pkt, len);
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case PKT_KEEPALIVE: return bgp_rx_keepalive(conn, pkt, len);
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default: bgp_error(conn, 1, 3, pkt[18], 1);
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}
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}
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int
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bgp_rx(sock *sk, int size)
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{
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struct bgp_conn *conn = sk->data;
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byte *pkt_start = sk->rbuf;
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byte *end = pkt_start + size;
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unsigned i, len;
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DBG("BGP: RX hook: Got %d bytes\n", size);
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while (end >= pkt_start + BGP_HEADER_LENGTH)
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{
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if (conn->error_flag)
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{
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DBG("BGP: Error, dropping input\n");
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return 1;
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}
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for(i=0; i<16; i++)
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if (pkt_start[i] != 0xff)
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{
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bgp_error(conn, 1, 1, 0, 0);
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break;
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}
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len = get_u16(pkt_start+16);
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if (len < BGP_HEADER_LENGTH || len > BGP_MAX_PACKET_LENGTH)
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{
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bgp_error(conn, 1, 2, len, 2);
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break;
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}
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if (end >= pkt_start + len)
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{
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bgp_rx_packet(conn, pkt_start, len);
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pkt_start += len;
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}
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}
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if (pkt_start != sk->rbuf)
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{
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memmove(sk->rbuf, pkt_start, end - pkt_start);
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sk->rpos = sk->rbuf + (end - pkt_start);
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}
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return 0;
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}
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