/src/frr/pimd/pim_pim.c

Source (jump to first uncovered line)
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * PIM for Quagga
 * Copyright (C) 2008  Everton da Silva Marques
 */

#include <zebra.h>

#include "log.h"
#include "frrevent.h"
#include "memory.h"
#include "if.h"
#include "network.h"

#include "pimd.h"
#include "pim_instance.h"
#include "pim_pim.h"
#include "pim_time.h"
#include "pim_iface.h"
#include "pim_sock.h"
#include "pim_str.h"
#include "pim_util.h"
#include "pim_tlv.h"
#include "pim_neighbor.h"
#include "pim_hello.h"
#include "pim_join.h"
#include "pim_assert.h"
#include "pim_msg.h"
#include "pim_register.h"
#include "pim_errors.h"
#include "pim_bsm.h"
#include <lib/lib_errors.h>

static void on_pim_hello_send(struct event *t);

static const char *pim_pim_msgtype2str(enum pim_msg_type type)
{
  switch (type) {
  case PIM_MSG_TYPE_HELLO:
    return "HELLO";
  case PIM_MSG_TYPE_REGISTER:
    return "REGISTER";
  case PIM_MSG_TYPE_REG_STOP:
    return "REGSTOP";
  case PIM_MSG_TYPE_JOIN_PRUNE:
    return "JOINPRUNE";
  case PIM_MSG_TYPE_BOOTSTRAP:
    return "BOOT";
  case PIM_MSG_TYPE_ASSERT:
    return "ASSERT";
  case PIM_MSG_TYPE_GRAFT:
    return "GRAFT";
  case PIM_MSG_TYPE_GRAFT_ACK:
    return "GACK";
  case PIM_MSG_TYPE_CANDIDATE:
    return "CANDIDATE";
  }

  return "UNKNOWN";
}

static void sock_close(struct interface *ifp)
{
  struct pim_interface *pim_ifp = ifp->info;

  if (PIM_DEBUG_PIM_TRACE) {
    if (pim_ifp->t_pim_sock_read) {
      zlog_debug(
        "Cancelling READ event for PIM socket fd=%d on interface %s",
        pim_ifp->pim_sock_fd, ifp->name);
    }
  }
  EVENT_OFF(pim_ifp->t_pim_sock_read);

  if (PIM_DEBUG_PIM_TRACE) {
    if (pim_ifp->t_pim_hello_timer) {
      zlog_debug(
        "Cancelling PIM hello timer for interface %s",
        ifp->name);
    }
  }
  EVENT_OFF(pim_ifp->t_pim_hello_timer);

  if (PIM_DEBUG_PIM_TRACE) {
    zlog_debug("Deleting PIM socket fd=%d on interface %s",
         pim_ifp->pim_sock_fd, ifp->name);
  }

  /*
   * If the fd is already deleted no need to do anything here
   */
  if (pim_ifp->pim_sock_fd > 0 && close(pim_ifp->pim_sock_fd)) {
    zlog_warn(
      "Failure closing PIM socket fd=%d on interface %s: errno=%d: %s",
      pim_ifp->pim_sock_fd, ifp->name, errno,
      safe_strerror(errno));
  }

  pim_ifp->pim_sock_fd = -1;
  pim_ifp->pim_sock_creation = 0;
}

void pim_sock_delete(struct interface *ifp, const char *delete_message)
{
  zlog_info("PIM INTERFACE DOWN: on interface %s: %s", ifp->name,
      delete_message);

  if (!ifp->info) {
    flog_err(EC_PIM_CONFIG,
       "%s: %s: but PIM not enabled on interface %s (!)",
       __func__, delete_message, ifp->name);
    return;
  }

  /*
    RFC 4601: 4.3.1.  Sending Hello Messages

    Before an interface goes down or changes primary IP address, a Hello
    message with a zero HoldTime should be sent immediately (with the
    old IP address if the IP address changed).
  */
  pim_hello_send(ifp, 0 /* zero-sec holdtime */);

  pim_neighbor_delete_all(ifp, delete_message);

  sock_close(ifp);
}

/* For now check dst address for hello, assrt and join/prune is all pim rtr */
static bool pim_pkt_dst_addr_ok(enum pim_msg_type type, pim_addr addr)
{
  if ((type == PIM_MSG_TYPE_HELLO) || (type == PIM_MSG_TYPE_ASSERT)
      || (type == PIM_MSG_TYPE_JOIN_PRUNE)) {
    if (pim_addr_cmp(addr, qpim_all_pim_routers_addr))
      return false;
  }

  return true;
}

int pim_pim_packet(struct interface *ifp, uint8_t *buf, size_t len,
       pim_sgaddr sg)
{
  struct iovec iov[2], *iovp = iov;
#if PIM_IPV == 4
  struct ip *ip_hdr = (struct ip *)buf;
  size_t ip_hlen; /* ip header length in bytes */
#endif
  uint8_t *pim_msg;
  uint32_t pim_msg_len = 0;
  uint16_t pim_checksum; /* received checksum */
  uint16_t checksum;     /* computed checksum */
  struct pim_neighbor *neigh;
  struct pim_msg_header *header;
  bool   no_fwd;

#if PIM_IPV == 4
  if (len <= sizeof(*ip_hdr)) {
    if (PIM_DEBUG_PIM_PACKETS)
      zlog_debug(
        "PIM packet size=%zu shorter than minimum=%zu",
        len, sizeof(*ip_hdr));
    return -1;
  }

  ip_hlen = ip_hdr->ip_hl << 2; /* ip_hl gives length in 4-byte words */
#ifdef FUZZING
  /*
   * Ensure that the header length is 20 or 24 bytes as is appropriate
   * The kernel typically ensures that the passed up ip header meets
   * standards, and would actually drop the packet if it didn't meet
   * them.  So since we are fuzzing and faking the header bits/bobs
   * then let's ensure that we don't get into a weird situation
   * where a bad ip_hlen here causes pim_msg_len to wrap around into
   * the high billions and then we have an issue later
   */
  if (ip_hlen != 20 && ip_hlen != 24)
    return -1;
#endif
  sg = pim_sgaddr_from_iphdr(ip_hdr);

  pim_msg = buf + ip_hlen;
  pim_msg_len = len - ip_hlen;
#else
  struct ipv6_ph phdr = {
    .src = sg.src,
    .dst = sg.grp,
    .ulpl = htonl(len),
    .next_hdr = IPPROTO_PIM,
  };

  iovp->iov_base = &phdr;
  iovp->iov_len = sizeof(phdr);
  iovp++;

  /* NB: header is not included in IPv6 RX */
  pim_msg = buf;
  pim_msg_len = len;
#endif

  iovp->iov_base = pim_msg;
  iovp->iov_len = pim_msg_len;
  iovp++;

  if (pim_msg_len < PIM_PIM_MIN_LEN) {
    if (PIM_DEBUG_PIM_PACKETS)
      zlog_debug(
        "PIM message size=%d shorter than minimum=%d",
        pim_msg_len, PIM_PIM_MIN_LEN);
    return -1;
  }
  header = (struct pim_msg_header *)pim_msg;

  if (header->ver != PIM_PROTO_VERSION) {
    if (PIM_DEBUG_PIM_PACKETS)
      zlog_debug(
        "Ignoring PIM pkt from %s with unsupported version: %d",
        ifp->name, header->ver);
    return -1;
  }

  /* save received checksum */
  pim_checksum = header->checksum;

  /* for computing checksum */
  header->checksum = 0;
  no_fwd = header->Nbit;

  if (header->type == PIM_MSG_TYPE_REGISTER) {
    if (pim_msg_len < PIM_MSG_REGISTER_LEN) {
      if (PIM_DEBUG_PIM_PACKETS)
        zlog_debug("PIM Register Message size=%d shorther than min length %d",
             pim_msg_len, PIM_MSG_REGISTER_LEN);
      return -1;
    }

#if PIM_IPV == 6
    phdr.ulpl = htonl(PIM_MSG_REGISTER_LEN);
#endif
    /* First 8 byte header checksum */
    iovp[-1].iov_len = PIM_MSG_REGISTER_LEN;
    checksum = in_cksumv(iov, iovp - iov);

    if (checksum != pim_checksum) {
#if PIM_IPV == 6
      phdr.ulpl = htonl(pim_msg_len);
#endif
      iovp[-1].iov_len = pim_msg_len;

      checksum = in_cksumv(iov, iovp - iov);
      if (checksum != pim_checksum) {
        if (PIM_DEBUG_PIM_PACKETS)
          zlog_debug(
            "Ignoring PIM pkt from %s with invalid checksum: received=%x calculated=%x",
            ifp->name, pim_checksum,
            checksum);
#ifndef FUZZING
        return -1;
#endif
      }
    }
  } else {
    checksum = in_cksumv(iov, iovp - iov);
    if (checksum != pim_checksum) {
      if (PIM_DEBUG_PIM_PACKETS)
        zlog_debug(
          "Ignoring PIM pkt from %s with invalid checksum: received=%x calculated=%x",
          ifp->name, pim_checksum, checksum);
#ifndef FUZZING
      return -1;
#endif
    }
  }

  if (PIM_DEBUG_PIM_PACKETS) {
    zlog_debug(
      "Recv PIM %s packet from %pPA to %pPA on %s: pim_version=%d pim_msg_size=%d checksum=%x",
      pim_pim_msgtype2str(header->type), &sg.src, &sg.grp,
      ifp->name, header->ver, pim_msg_len, checksum);
    if (PIM_DEBUG_PIM_PACKETDUMP_RECV)
      pim_pkt_dump(__func__, pim_msg, pim_msg_len);
  }

  if (!pim_pkt_dst_addr_ok(header->type, sg.grp)) {
    zlog_warn(
      "%s: Ignoring Pkt. Unexpected IP destination %pPA for %s (Expected: all_pim_routers_addr) from %pPA",
      __func__, &sg.grp, pim_pim_msgtype2str(header->type),
      &sg.src);
    return -1;
  }

  switch (header->type) {
  case PIM_MSG_TYPE_HELLO:
    return pim_hello_recv(ifp, sg.src, pim_msg + PIM_MSG_HEADER_LEN,
              pim_msg_len - PIM_MSG_HEADER_LEN);
    break;
  case PIM_MSG_TYPE_REGISTER:
    return pim_register_recv(ifp, sg.grp, sg.src,
           pim_msg + PIM_MSG_HEADER_LEN,
           pim_msg_len - PIM_MSG_HEADER_LEN);
    break;
  case PIM_MSG_TYPE_REG_STOP:
    return pim_register_stop_recv(ifp, pim_msg + PIM_MSG_HEADER_LEN,
                pim_msg_len - PIM_MSG_HEADER_LEN);
    break;
  case PIM_MSG_TYPE_JOIN_PRUNE:
    neigh = pim_neighbor_find(ifp, sg.src, false);
    if (!neigh) {
      if (PIM_DEBUG_PIM_PACKETS)
        zlog_debug(
          "%s %s: non-hello PIM message type=%d from non-neighbor %pPA on %s",
          __FILE__, __func__, header->type,
          &sg.src, ifp->name);
      return -1;
    }
    pim_neighbor_timer_reset(neigh, neigh->holdtime);
    return pim_joinprune_recv(ifp, neigh, sg.src,
            pim_msg + PIM_MSG_HEADER_LEN,
            pim_msg_len - PIM_MSG_HEADER_LEN);
    break;
  case PIM_MSG_TYPE_ASSERT:
    neigh = pim_neighbor_find(ifp, sg.src, false);
    if (!neigh) {
      if (PIM_DEBUG_PIM_PACKETS)
        zlog_debug(
          "%s %s: non-hello PIM message type=%d from non-neighbor %pPA on %s",
          __FILE__, __func__, header->type,
          &sg.src, ifp->name);
      return -1;
    }
    pim_neighbor_timer_reset(neigh, neigh->holdtime);
    return pim_assert_recv(ifp, neigh, sg.src,
               pim_msg + PIM_MSG_HEADER_LEN,
               pim_msg_len - PIM_MSG_HEADER_LEN);
    break;
  case PIM_MSG_TYPE_BOOTSTRAP:
    return pim_bsm_process(ifp, &sg, pim_msg, pim_msg_len, no_fwd);
    break;

  default:
    if (PIM_DEBUG_PIM_PACKETS) {
      zlog_debug(
        "Recv PIM packet type %d which is not currently understood",
        header->type);
    }
    return -1;
  }
}

static void pim_sock_read_on(struct interface *ifp);

static void pim_sock_read(struct event *t)
{
  struct interface *ifp, *orig_ifp;
  struct pim_interface *pim_ifp;
  int fd;
  struct sockaddr_storage from;
  struct sockaddr_storage to;
  socklen_t fromlen = sizeof(from);
  socklen_t tolen = sizeof(to);
  uint8_t buf[PIM_PIM_BUFSIZE_READ];
  int len;
  ifindex_t ifindex = -1;
  int result = -1; /* defaults to bad */
  static long long count = 0;
  int cont = 1;

  orig_ifp = ifp = EVENT_ARG(t);
  fd = EVENT_FD(t);

  pim_ifp = ifp->info;

  while (cont) {
    pim_sgaddr sg;

    len = pim_socket_recvfromto(fd, buf, sizeof(buf), &from,
              &fromlen, &to, &tolen, &ifindex);
    if (len < 0) {
      if (errno == EINTR)
        continue;
      if (errno == EWOULDBLOCK || errno == EAGAIN)
        break;

      if (PIM_DEBUG_PIM_PACKETS)
        zlog_debug("Received errno: %d %s", errno,
             safe_strerror(errno));
      goto done;
    }

    /*
     * What?  So with vrf's the incoming packet is received
     * on the vrf interface but recvfromto above returns
     * the right ifindex, so just use it.  We know
     * it's the right interface because we bind to it
     */
    ifp = if_lookup_by_index(ifindex, pim_ifp->pim->vrf->vrf_id);
    if (!ifp || !ifp->info) {
      if (PIM_DEBUG_PIM_PACKETS)
        zlog_debug(
          "%s: Received incoming pim packet on interface(%s:%d) not yet configured for pim",
          __func__, ifp ? ifp->name : "Unknown",
          ifindex);
      goto done;
    }
#if PIM_IPV == 4
    sg.src = ((struct sockaddr_in *)&from)->sin_addr;
    sg.grp = ((struct sockaddr_in *)&to)->sin_addr;
#else
    sg.src = ((struct sockaddr_in6 *)&from)->sin6_addr;
    sg.grp = ((struct sockaddr_in6 *)&to)->sin6_addr;
#endif

    int fail = pim_pim_packet(ifp, buf, len, sg);
    if (fail) {
      if (PIM_DEBUG_PIM_PACKETS)
        zlog_debug("%s: pim_pim_packet() return=%d",
             __func__, fail);
      goto done;
    }

    count++;
    if (count % router->packet_process == 0)
      cont = 0;
  }

  result = 0; /* good */

done:
  pim_sock_read_on(orig_ifp);

  if (result) {
    ++pim_ifp->pim_ifstat_hello_recvfail;
  }
}

static void pim_sock_read_on(struct interface *ifp)
{
  struct pim_interface *pim_ifp;

  assert(ifp);
  assert(ifp->info);

  pim_ifp = ifp->info;

  if (PIM_DEBUG_PIM_TRACE_DETAIL) {
    zlog_debug("Scheduling READ event on PIM socket fd=%d",
         pim_ifp->pim_sock_fd);
  }
  event_add_read(router->master, pim_sock_read, ifp, pim_ifp->pim_sock_fd,
           &pim_ifp->t_pim_sock_read);
}

static int pim_sock_open(struct interface *ifp)
{
  int fd;
  struct pim_interface *pim_ifp = ifp->info;

  fd = pim_socket_mcast(IPPROTO_PIM, pim_ifp->primary_address, ifp,
            0 /* loop=false */);
  if (fd < 0)
    return -1;

  if (pim_socket_join(fd, qpim_all_pim_routers_addr,
          pim_ifp->primary_address, ifp->ifindex, pim_ifp)) {
    close(fd);
    return -2;
  }

  return fd;
}

void pim_ifstat_reset(struct interface *ifp)
{
  struct pim_interface *pim_ifp;

  assert(ifp);

  pim_ifp = ifp->info;
  if (!pim_ifp) {
    return;
  }

  pim_ifp->pim_ifstat_start = pim_time_monotonic_sec();
  pim_ifp->pim_ifstat_hello_sent = 0;
  pim_ifp->pim_ifstat_hello_sendfail = 0;
  pim_ifp->pim_ifstat_hello_recv = 0;
  pim_ifp->pim_ifstat_hello_recvfail = 0;
  pim_ifp->pim_ifstat_bsm_rx = 0;
  pim_ifp->pim_ifstat_bsm_tx = 0;
  pim_ifp->pim_ifstat_join_recv = 0;
  pim_ifp->pim_ifstat_join_send = 0;
  pim_ifp->pim_ifstat_prune_recv = 0;
  pim_ifp->pim_ifstat_prune_send = 0;
  pim_ifp->pim_ifstat_reg_recv = 0;
  pim_ifp->pim_ifstat_reg_send = 0;
  pim_ifp->pim_ifstat_reg_stop_recv = 0;
  pim_ifp->pim_ifstat_reg_stop_send = 0;
  pim_ifp->pim_ifstat_assert_recv = 0;
  pim_ifp->pim_ifstat_assert_send = 0;
  pim_ifp->pim_ifstat_bsm_cfg_miss = 0;
  pim_ifp->pim_ifstat_ucast_bsm_cfg_miss = 0;
  pim_ifp->pim_ifstat_bsm_invalid_sz = 0;
  pim_ifp->igmp_ifstat_joins_sent = 0;
  pim_ifp->igmp_ifstat_joins_failed = 0;
  pim_ifp->igmp_peak_group_count = 0;
}

void pim_sock_reset(struct interface *ifp)
{
  struct pim_interface *pim_ifp;

  assert(ifp);
  assert(ifp->info);

  pim_ifp = ifp->info;

  pim_ifp->primary_address = pim_find_primary_addr(ifp);

  pim_ifp->pim_sock_fd = -1;
  pim_ifp->pim_sock_creation = 0;
  pim_ifp->t_pim_sock_read = NULL;

  pim_ifp->t_pim_hello_timer = NULL;
  pim_ifp->pim_hello_period = PIM_DEFAULT_HELLO_PERIOD;
  pim_ifp->pim_default_holdtime =
    -1; /* unset: means 3.5 * pim_hello_period */
  pim_ifp->pim_triggered_hello_delay = PIM_DEFAULT_TRIGGERED_HELLO_DELAY;
  pim_ifp->pim_dr_priority = PIM_DEFAULT_DR_PRIORITY;
  pim_ifp->pim_propagation_delay_msec =
    PIM_DEFAULT_PROPAGATION_DELAY_MSEC;
  pim_ifp->pim_override_interval_msec =
    PIM_DEFAULT_OVERRIDE_INTERVAL_MSEC;
  pim_ifp->pim_can_disable_join_suppression =
    PIM_DEFAULT_CAN_DISABLE_JOIN_SUPPRESSION;

  /* neighbors without lan_delay */
  pim_ifp->pim_number_of_nonlandelay_neighbors = 0;
  pim_ifp->pim_neighbors_highest_propagation_delay_msec = 0;
  pim_ifp->pim_neighbors_highest_override_interval_msec = 0;

  /* DR Election */
  pim_ifp->pim_dr_election_last = 0; /* timestamp */
  pim_ifp->pim_dr_election_count = 0;
  pim_ifp->pim_dr_election_changes = 0;
  pim_ifp->pim_dr_num_nondrpri_neighbors =
    0; /* neighbors without dr_pri */
  pim_ifp->pim_dr_addr = pim_ifp->primary_address;
  pim_ifp->am_i_dr = true;

  pim_ifstat_reset(ifp);
}

#if PIM_IPV == 4
static uint16_t ip_id = 0;
#endif

#if PIM_IPV == 4
static int pim_msg_send_frame(int fd, char *buf, size_t len,
            struct sockaddr *dst, size_t salen,
            const char *ifname)
{
  if (sendto(fd, buf, len, MSG_DONTWAIT, dst, salen) >= 0)
    return 0;

  if (errno == EMSGSIZE) {
    struct ip *ip = (struct ip *)buf;
    size_t hdrsize = sizeof(struct ip);
    size_t newlen1 = ((len - hdrsize) / 2) & 0xFFF8;
    size_t sendlen = newlen1 + hdrsize;
    size_t offset = ntohs(ip->ip_off);
    int ret;

    ip->ip_len = htons(sendlen);
    ip->ip_off = htons(offset | IP_MF);

    ret = pim_msg_send_frame(fd, buf, sendlen, dst, salen, ifname);
    if (ret)
      return ret;

    struct ip *ip2 = (struct ip *)(buf + newlen1);
    size_t newlen2 = len - sendlen;

    sendlen = newlen2 + hdrsize;

    memcpy(ip2, ip, hdrsize);
    ip2->ip_len = htons(sendlen);
    ip2->ip_off = htons(offset + (newlen1 >> 3));
    return pim_msg_send_frame(fd, (char *)ip2, sendlen, dst, salen,
            ifname);
  }

  zlog_warn(
    "%s: sendto() failure to %pSU: iface=%s fd=%d msg_size=%zd: %m",
    __func__, dst, ifname, fd, len);
  return -1;
}

#else
static int pim_msg_send_frame(pim_addr src, pim_addr dst, ifindex_t ifindex,
            struct iovec *message, int fd)
{
  int retval;
  struct msghdr smsghdr = {};
  struct cmsghdr *scmsgp;
  union cmsgbuf {
    struct cmsghdr hdr;
    uint8_t buf[CMSG_SPACE(sizeof(struct in6_pktinfo))];
  };
  struct in6_pktinfo *pktinfo;
  struct sockaddr_in6 dst_sin6 = {};

  union cmsgbuf cmsg_buf = {};

  /* destination address */
  dst_sin6.sin6_family = AF_INET6;
#ifdef SIN6_LEN
  dst_sin6.sin6_len = sizeof(struct sockaddr_in6);
#endif /*SIN6_LEN*/
  dst_sin6.sin6_addr = dst;
  dst_sin6.sin6_scope_id = ifindex;

  /* send msg hdr */
  smsghdr.msg_iov = message;
  smsghdr.msg_iovlen = 1;
  smsghdr.msg_name = (caddr_t)&dst_sin6;
  smsghdr.msg_namelen = sizeof(dst_sin6);
  smsghdr.msg_control = (caddr_t)&cmsg_buf.buf;
  smsghdr.msg_controllen = CMSG_SPACE(sizeof(struct in6_pktinfo));
  smsghdr.msg_flags = 0;

  scmsgp = CMSG_FIRSTHDR(&smsghdr);
  scmsgp->cmsg_level = IPPROTO_IPV6;
  scmsgp->cmsg_type = IPV6_PKTINFO;
  scmsgp->cmsg_len = CMSG_LEN(sizeof(struct in6_pktinfo));

  pktinfo = (struct in6_pktinfo *)(CMSG_DATA(scmsgp));
  pktinfo->ipi6_ifindex = ifindex;
  pktinfo->ipi6_addr = src;

  retval = sendmsg(fd, &smsghdr, 0);
  if (retval < 0)
    flog_err(
      EC_LIB_SOCKET,
      "sendmsg failed: source: %pI6 Dest: %pI6 ifindex: %d: %s (%d)",
      &src, &dst, ifindex, safe_strerror(errno), errno);

  return retval;
}
#endif

int pim_msg_send(int fd, pim_addr src, pim_addr dst, uint8_t *pim_msg,
     int pim_msg_size, struct interface *ifp)
{
  struct pim_interface *pim_ifp;


  pim_ifp = ifp->info;

  if (pim_ifp->pim_passive_enable) {
    if (PIM_DEBUG_PIM_PACKETS)
      zlog_debug(
        "skip sending PIM message on passive interface %s",
        ifp->name);
    return 0;
  }

#if PIM_IPV == 4
  uint8_t ttl;
  struct pim_msg_header *header;
  unsigned char buffer[10000];

  memset(buffer, 0, 10000);

  header = (struct pim_msg_header *)pim_msg;

/*
 * Omnios apparently doesn't have a #define for IP default
 * ttl that is the same as all other platforms.
 */
#ifndef IPDEFTTL
#define IPDEFTTL   64
#endif
  /* TTL for packets destine to ALL-PIM-ROUTERS is 1 */
  switch (header->type) {
  case PIM_MSG_TYPE_HELLO:
  case PIM_MSG_TYPE_JOIN_PRUNE:
  case PIM_MSG_TYPE_BOOTSTRAP:
  case PIM_MSG_TYPE_ASSERT:
    ttl = 1;
    break;
  case PIM_MSG_TYPE_REGISTER:
  case PIM_MSG_TYPE_REG_STOP:
  case PIM_MSG_TYPE_GRAFT:
  case PIM_MSG_TYPE_GRAFT_ACK:
  case PIM_MSG_TYPE_CANDIDATE:
    ttl = IPDEFTTL;
    break;
  default:
    ttl = MAXTTL;
    break;
  }

  struct ip *ip = (struct ip *)buffer;
  struct sockaddr_in to = {};
  int sendlen = sizeof(*ip) + pim_msg_size;
  socklen_t tolen;
  unsigned char *msg_start;

  ip->ip_id = htons(++ip_id);
  ip->ip_hl = 5;
  ip->ip_v = 4;
  ip->ip_tos = IPTOS_PREC_INTERNETCONTROL;
  ip->ip_p = PIM_IP_PROTO_PIM;
  ip->ip_src = src;
  ip->ip_dst = dst;
  ip->ip_ttl = ttl;
  ip->ip_len = htons(sendlen);

  to.sin_family = AF_INET;
  to.sin_addr = dst;
  tolen = sizeof(to);

  msg_start = buffer + sizeof(*ip);
  memcpy(msg_start, pim_msg, pim_msg_size);

  if (PIM_DEBUG_PIM_PACKETS)
    zlog_debug("%s: to %pPA on %s: msg_size=%d checksum=%x",
         __func__, &dst, ifp->name, pim_msg_size,
         header->checksum);

  if (PIM_DEBUG_PIM_PACKETDUMP_SEND) {
    pim_pkt_dump(__func__, pim_msg, pim_msg_size);
  }

  pim_msg_send_frame(fd, (char *)buffer, sendlen, (struct sockaddr *)&to,
         tolen, ifp->name);
  return 0;

#else
  struct iovec iovector[2];

  iovector[0].iov_base = pim_msg;
  iovector[0].iov_len = pim_msg_size;

  pim_msg_send_frame(src, dst, ifp->ifindex, &iovector[0], fd);

  return 0;
#endif
}

static int hello_send(struct interface *ifp, uint16_t holdtime)
{
  uint8_t pim_msg[PIM_PIM_BUFSIZE_WRITE];
  struct pim_interface *pim_ifp;
  int pim_tlv_size;
  int pim_msg_size;

  pim_ifp = ifp->info;

  if (PIM_DEBUG_PIM_HELLO)
    zlog_debug(
      "%s: to %pPA on %s: holdt=%u prop_d=%u overr_i=%u dis_join_supp=%d dr_prio=%u gen_id=%08x addrs=%d",
      __func__, &qpim_all_pim_routers_addr, ifp->name,
      holdtime, pim_ifp->pim_propagation_delay_msec,
      pim_ifp->pim_override_interval_msec,
      pim_ifp->pim_can_disable_join_suppression,
      pim_ifp->pim_dr_priority, pim_ifp->pim_generation_id,
      listcount(ifp->connected));

  pim_tlv_size = pim_hello_build_tlv(
    ifp, pim_msg + PIM_PIM_MIN_LEN,
    sizeof(pim_msg) - PIM_PIM_MIN_LEN, holdtime,
    pim_ifp->pim_dr_priority, pim_ifp->pim_generation_id,
    pim_ifp->pim_propagation_delay_msec,
    pim_ifp->pim_override_interval_msec,
    pim_ifp->pim_can_disable_join_suppression);
  if (pim_tlv_size < 0) {
    return -1;
  }

  pim_msg_size = pim_tlv_size + PIM_PIM_MIN_LEN;

  assert(pim_msg_size >= PIM_PIM_MIN_LEN);
  assert(pim_msg_size <= PIM_PIM_BUFSIZE_WRITE);

  pim_msg_build_header(pim_ifp->primary_address,
           qpim_all_pim_routers_addr, pim_msg, pim_msg_size,
           PIM_MSG_TYPE_HELLO, false);

  if (pim_msg_send(pim_ifp->pim_sock_fd, pim_ifp->primary_address,
       qpim_all_pim_routers_addr, pim_msg, pim_msg_size,
       ifp)) {
    if (PIM_DEBUG_PIM_HELLO) {
      zlog_debug(
        "%s: could not send PIM message on interface %s",
        __func__, ifp->name);
    }
    return -2;
  }

  return 0;
}

int pim_hello_send(struct interface *ifp, uint16_t holdtime)
{
  struct pim_interface *pim_ifp = ifp->info;

  if (if_is_loopback(ifp))
    return 0;

  if (hello_send(ifp, holdtime)) {
    ++pim_ifp->pim_ifstat_hello_sendfail;

    if (PIM_DEBUG_PIM_HELLO) {
      zlog_warn("Could not send PIM hello on interface %s",
          ifp->name);
    }
    return -1;
  }

  if (!pim_ifp->pim_passive_enable) {
    ++pim_ifp->pim_ifstat_hello_sent;
    PIM_IF_FLAG_SET_HELLO_SENT(pim_ifp->flags);
  }

  return 0;
}

static void hello_resched(struct interface *ifp)
{
  struct pim_interface *pim_ifp;

  pim_ifp = ifp->info;

  if (PIM_DEBUG_PIM_HELLO) {
    zlog_debug("Rescheduling %d sec hello on interface %s",
         pim_ifp->pim_hello_period, ifp->name);
  }
  EVENT_OFF(pim_ifp->t_pim_hello_timer);
  event_add_timer(router->master, on_pim_hello_send, ifp,
      pim_ifp->pim_hello_period, &pim_ifp->t_pim_hello_timer);
}

/*
  Periodic hello timer
 */
static void on_pim_hello_send(struct event *t)
{
  struct pim_interface *pim_ifp;
  struct interface *ifp;

  ifp = EVENT_ARG(t);
  pim_ifp = ifp->info;

  /*
   * Schedule next hello
   */
  hello_resched(ifp);

  /*
   * Send hello
   */
  pim_hello_send(ifp, PIM_IF_DEFAULT_HOLDTIME(pim_ifp));
}

/*
  RFC 4601: 4.3.1.  Sending Hello Messages

  Thus, if a router needs to send a Join/Prune or Assert message on an
  interface on which it has not yet sent a Hello message with the
  currently configured IP address, then it MUST immediately send the
  relevant Hello message without waiting for the Hello Timer to
  expire, followed by the Join/Prune or Assert message.
 */
void pim_hello_restart_now(struct interface *ifp)
{
  struct pim_interface *pim_ifp;

  pim_ifp = ifp->info;

  /*
   * Reset next hello timer
   */
  hello_resched(ifp);

  /*
   * Immediately send hello
   */
  pim_hello_send(ifp, PIM_IF_DEFAULT_HOLDTIME(pim_ifp));
}

/*
  RFC 4601: 4.3.1.  Sending Hello Messages

  To allow new or rebooting routers to learn of PIM neighbors quickly,
  when a Hello message is received from a new neighbor, or a Hello
  message with a new GenID is received from an existing neighbor, a
  new Hello message should be sent on this interface after a
  randomized delay between 0 and Triggered_Hello_Delay.
 */
void pim_hello_restart_triggered(struct interface *ifp)
{
  struct pim_interface *pim_ifp;
  int triggered_hello_delay_msec;
  int random_msec;

  pim_ifp = ifp->info;

  /*
   * No need to ever start loopback or vrf device hello's
   */
  if (if_is_loopback(ifp))
    return;

  /*
   * There exists situations where we have the a RPF out this
   * interface, but we haven't formed a neighbor yet.  This
   * happens especially during interface flaps.  While
   * we would like to handle this more gracefully in other
   * parts of the code.  In order to get us up and running
   * let's just send the hello immediate'ish
   * This should be revisited when we get nexthop tracking
   * in and when we have a better handle on safely
   * handling the rpf information for upstreams that
   * we cannot legally reach yet.
   */
  triggered_hello_delay_msec = 1;
  // triggered_hello_delay_msec = 1000 *
  // pim_ifp->pim_triggered_hello_delay;

  if (pim_ifp->t_pim_hello_timer) {
    long remain_msec =
      pim_time_timer_remain_msec(pim_ifp->t_pim_hello_timer);
    if (remain_msec <= triggered_hello_delay_msec) {
      /* Rescheduling hello would increase the delay, then
         it's faster
         to just wait for the scheduled periodic hello. */
      return;
    }

    EVENT_OFF(pim_ifp->t_pim_hello_timer);
  }

  random_msec = triggered_hello_delay_msec;
  // random_msec = random() % (triggered_hello_delay_msec + 1);

  if (PIM_DEBUG_PIM_HELLO) {
    zlog_debug("Scheduling %d msec triggered hello on interface %s",
         random_msec, ifp->name);
  }

  event_add_timer_msec(router->master, on_pim_hello_send, ifp,
           random_msec, &pim_ifp->t_pim_hello_timer);
}

int pim_sock_add(struct interface *ifp)
{
  struct pim_interface *pim_ifp;
  uint32_t old_genid;

  pim_ifp = ifp->info;
  assert(pim_ifp);

  if (pim_ifp->pim_sock_fd >= 0) {
    if (PIM_DEBUG_PIM_PACKETS)
      zlog_debug(
        "Can't recreate existing PIM socket fd=%d for interface %s",
        pim_ifp->pim_sock_fd, ifp->name);
    return -1;
  }

  pim_ifp->pim_sock_fd = pim_sock_open(ifp);
  if (pim_ifp->pim_sock_fd < 0) {
    if (PIM_DEBUG_PIM_PACKETS)
      zlog_debug("Could not open PIM socket on interface %s",
           ifp->name);
    return -2;
  }

  pim_socket_ip_hdr(pim_ifp->pim_sock_fd);

  pim_ifp->t_pim_sock_read = NULL;
  pim_ifp->pim_sock_creation = pim_time_monotonic_sec();

  /*
   * Just ensure that the new generation id
   * actually chooses something different.
   * Actually ran across a case where this
   * happened, pre-switch to random().
   * While this is unlikely to happen now
   * let's make sure it doesn't.
   */
  old_genid = pim_ifp->pim_generation_id;

  while (old_genid == pim_ifp->pim_generation_id)
    pim_ifp->pim_generation_id = frr_weak_random();

  zlog_info("PIM INTERFACE UP: on interface %s ifindex=%d", ifp->name,
      ifp->ifindex);

  /*
   * Start receiving PIM messages
   */
  pim_sock_read_on(ifp);

  /*
   * Start sending PIM hello's
   */
  pim_hello_restart_triggered(ifp);

  return 0;
}

Coverage Report

Created: 2025-08-26 06:20