Many changes in I/O and OSPF sockets and packet handling.

I/O:
 - BSD: specify src addr on IP sockets by IP_HDRINCL
 - BSD: specify src addr on UDP sockets by IP_SENDSRCADDR
 - Linux: specify src addr on IP/UDP sockets by IP_PKTINFO
 - IPv6: specify src addr on IP/UDP sockets by IPV6_PKTINFO
 - Alternative SKF_BIND flag for binding to IP address
 - Allows IP/UDP sockets without tx_hook, on these
   sockets a packet is discarded when TX queue is full
 - Use consistently SOL_ for socket layer values.

OSPF:
 - Packet src addr is always explicitly set
 - Support for secondary addresses in BSD
 - Dynamic RX/TX buffers
 - Fixes some minor buffer overruns
 - Interface option 'tx length'
 - Names for vlink pseudoifaces (vlinkX)
 - Vlinks use separate socket for TX
 - Vlinks do not use fixed associated iface
 - Fixes TTL for direct unicast packets
 - Fixes DONTROUTE for OSPF sockets
 - Use ifa->ifname instead of ifa->iface->name

5 files changed, 256 insertions, 150 deletions

diff --git a/sysdep/bsd/sysio.h b/sysdep/bsd/sysio.h
index cf049a0b..e45deb6f 100644
--- a/sysdep/bsd/sysio.h
+++ b/sysdep/bsd/sysio.h
@@ -38,18 +38,13 @@ get_inaddr(ip_addr *a, struct in6_addr *ia)
   ipa_ntoh(*a);
 }
 
-static inline char *
-sysio_bind_to_iface(sock *s)
-{
-  /* Unfortunately not available */
-  return NULL;
-}
-
 
 #else
 
 #include <net/if.h>
 #include <net/if_dl.h>
+#include <netinet/in_systm.h> // Workaround for some BSDs
+#include <netinet/ip.h>
 
 static inline void
 set_inaddr(struct in_addr * ia, ip_addr a)
@@ -93,7 +88,7 @@ sysio_setup_multicast(sock *s)
 static inline char *
 sysio_join_group(sock *s, ip_addr maddr)
 {
-	struct ip_mreq  mreq;
+	struct ip_mreq mreq;
 
 	bzero(&mreq, sizeof(mreq));
 	set_inaddr(&mreq.imr_interface, s->iface->addr->ip);
@@ -152,7 +147,7 @@ sysio_register_cmsgs(sock *s)
   return NULL;
 }
 
-static void
+static inline void
 sysio_process_rx_cmsgs(sock *s, struct msghdr *msg)
 {
   struct cmsghdr *cm;
@@ -190,26 +185,17 @@ sysio_process_rx_cmsgs(sock *s, struct msghdr *msg)
 }
 
 /* Unfortunately, IP_SENDSRCADDR does not work for raw IP sockets on BSD kernels */
-/*
-static void
+
+static inline void
 sysio_prepare_tx_cmsgs(sock *s, struct msghdr *msg, void *cbuf, size_t cbuflen)
 {
+#ifdef IP_SENDSRCADDR
   struct cmsghdr *cm;
   struct in_addr *sa;
 
-  if (!(s->flags & SKF_LADDR_TX))
-    return;
-
   msg->msg_control = cbuf;
   msg->msg_controllen = cbuflen;
 
-  if (s->iface)
-    {
-      struct in_addr m;
-      set_inaddr(&m, s->saddr);
-      setsockopt(s->fd, IPPROTO_IP, IP_MULTICAST_IF, &m, sizeof(m));
-    }
-
   cm = CMSG_FIRSTHDR(msg);
   cm->cmsg_level = IPPROTO_IP;
   cm->cmsg_type = IP_SENDSRCADDR;
@@ -219,8 +205,31 @@ sysio_prepare_tx_cmsgs(sock *s, struct msghdr *msg, void *cbuf, size_t cbuflen)
   set_inaddr(sa, s->saddr);
 
   msg->msg_controllen = cm->cmsg_len;
+#endif
+}
+
+
+static void
+fill_ip_header(sock *s, void *hdr, int dlen)
+{
+  struct ip *ip = hdr;
+
+  bzero(ip, 20);
+
+  ip->ip_v = 4;
+  ip->ip_hl = 5;
+  ip->ip_tos = (s->tos < 0) ? 0 : s->tos;
+  ip->ip_len = 20 + dlen;
+  ip->ip_ttl = (s->ttl < 0) ? 64 : s->ttl;
+  ip->ip_p = s->dport;
+  set_inaddr(&ip->ip_src, s->saddr);
+  set_inaddr(&ip->ip_dst, s->daddr);
+
+#ifdef __OpenBSD__
+  /* OpenBSD expects ip_len in network order, other BSDs expect host order */
+  ip->ip_len = htons(ip->ip_len);
+#endif
 }
-*/
 
 #endif
 
diff --git a/sysdep/cf/README b/sysdep/cf/README
index 1c11edcf..768a3727 100644
--- a/sysdep/cf/README
+++ b/sysdep/cf/README
@@ -8,6 +8,8 @@ CONFIG_ALL_TABLES_AT_ONCE	Kernel scanner wants to process all tables at once
 
 CONFIG_MC_PROPER_SRC	Multicast packets have source address according to socket saddr field
 CONFIG_SKIP_MC_BIND	Don't call bind on multicast socket (def for *BSD)
+CONFIG_NO_IFACE_BIND	Bind to iface is not available, use workarounds (def for *BSD)
 CONFIG_UNIX_DONTROUTE	Use setsockopts DONTROUTE (undef for *BSD)
+CONFIG_USE_HDRINCL	Use IP_HDRINCL instead of control messages for source address on raw IP sockets.
 
 CONFIG_RESTRICTED_PRIVILEGES	Implements restricted privileges using drop_uid()
diff --git a/sysdep/cf/bsd.h b/sysdep/cf/bsd.h
index 5e6d03e8..df199199 100644
--- a/sysdep/cf/bsd.h
+++ b/sysdep/cf/bsd.h
@@ -12,6 +12,7 @@
 
 #define CONFIG_SKIP_MC_BIND
 #define CONFIG_NO_IFACE_BIND
+#define CONFIG_USE_HDRINCL
 
 /*
 Link: sysdep/unix
diff --git a/sysdep/linux/sysio.h b/sysdep/linux/sysio.h
index 250ed586..56c3387d 100644
--- a/sysdep/linux/sysio.h
+++ b/sysdep/linux/sysio.h
@@ -30,17 +30,6 @@ get_inaddr(ip_addr *a, struct in6_addr *ia)
   ipa_ntoh(*a);
 }
 
-static inline char *
-sysio_bind_to_iface(sock *s)
-{
-  struct ifreq ifr;
-  strcpy(ifr.ifr_name, s->iface->name);
-  if (setsockopt(s->fd, SOL_SOCKET, SO_BINDTODEVICE, &ifr, sizeof(ifr)) < 0)
-    return "SO_BINDTODEVICE";
-
-  return NULL;
-}
-
 #else
 
 static inline void
@@ -69,11 +58,10 @@ struct ip_mreqn
 #endif
 
 
-static inline void fill_mreqn(struct ip_mreqn *m, struct iface *ifa, ip_addr saddr, ip_addr maddr)
+static inline void fill_mreqn(struct ip_mreqn *m, ip_addr maddr, struct iface *ifa)
 {
   bzero(m, sizeof(*m));
   m->imr_ifindex = ifa->index;
-  set_inaddr(&m->imr_address, saddr);
   set_inaddr(&m->imr_multiaddr, maddr);
 }
 
@@ -90,16 +78,10 @@ sysio_setup_multicast(sock *s)
     return "IP_MULTICAST_TTL";
 
   /* This defines where should we send _outgoing_ multicasts */
-  fill_mreqn(&m, s->iface, s->saddr, IPA_NONE);
+  fill_mreqn(&m, IPA_NONE, s->iface);
   if (setsockopt(s->fd, SOL_IP, IP_MULTICAST_IF, &m, sizeof(m)) < 0)
     return "IP_MULTICAST_IF";
 
-  /* Is this necessary? */
-  struct ifreq ifr;
-  strcpy(ifr.ifr_name, s->iface->name);
-  if (setsockopt(s->fd, SOL_SOCKET, SO_BINDTODEVICE, &ifr, sizeof(ifr)) < 0)
-    return "SO_BINDTODEVICE";
-
   return NULL;
 }
 
@@ -109,7 +91,7 @@ sysio_join_group(sock *s, ip_addr maddr)
   struct ip_mreqn m;
 
   /* And this one sets interface for _receiving_ multicasts from */
-  fill_mreqn(&m, s->iface, s->saddr, maddr);
+  fill_mreqn(&m, maddr, s->iface);
   if (setsockopt(s->fd, SOL_IP, IP_ADD_MEMBERSHIP, &m, sizeof(m)) < 0)
     return "IP_ADD_MEMBERSHIP";
 
@@ -122,7 +104,7 @@ sysio_leave_group(sock *s, ip_addr maddr)
   struct ip_mreqn m;
 
   /* And this one sets interface for _receiving_ multicasts from */
-  fill_mreqn(&m, s->iface, s->saddr, maddr);
+  fill_mreqn(&m, maddr, s->iface);
   if (setsockopt(s->fd, SOL_IP, IP_DROP_MEMBERSHIP, &m, sizeof(m)) < 0)
     return "IP_DROP_MEMBERSHIP";
 
@@ -132,10 +114,7 @@ sysio_leave_group(sock *s, ip_addr maddr)
 #endif
 
 
-#include <linux/socket.h>
-#include <linux/tcp.h>
-
-/* For the case that we have older kernel headers */
+/* For the case that we have older libc headers */
 /* Copied from Linux kernel file include/linux/tcp.h */
 
 #ifndef TCP_MD5SIG
@@ -175,7 +154,7 @@ sk_set_md5_auth_int(sock *s, sockaddr *sa, char *passwd)
       memcpy(&md5.tcpm_key, passwd, len);
     }
 
-  int rv = setsockopt(s->fd, IPPROTO_TCP, TCP_MD5SIG, &md5, sizeof(md5));
+  int rv = setsockopt(s->fd, SOL_TCP, TCP_MD5SIG, &md5, sizeof(md5));
 
   if (rv < 0) 
     {
@@ -203,11 +182,11 @@ sysio_register_cmsgs(sock *s)
   int ok = 1;
 
   if ((s->flags & SKF_LADDR_RX) &&
-      (setsockopt(s->fd, IPPROTO_IP, IP_PKTINFO, &ok, sizeof(ok)) < 0))
+      (setsockopt(s->fd, SOL_IP, IP_PKTINFO, &ok, sizeof(ok)) < 0))
     return "IP_PKTINFO";
 
   if ((s->flags & SKF_TTL_RX) &&
-      (setsockopt(s->fd, IPPROTO_IP, IP_RECVTTL, &ok, sizeof(ok)) < 0))
+      (setsockopt(s->fd, SOL_IP, IP_RECVTTL, &ok, sizeof(ok)) < 0))
     return "IP_RECVTTL";
 
   return NULL;
@@ -222,10 +201,10 @@ sysio_process_rx_cmsgs(sock *s, struct msghdr *msg)
 
   for (cm = CMSG_FIRSTHDR(msg); cm != NULL; cm = CMSG_NXTHDR(msg, cm))
   {
-    if (cm->cmsg_level == IPPROTO_IP && cm->cmsg_type == IP_PKTINFO)
+    if (cm->cmsg_level == SOL_IP && cm->cmsg_type == IP_PKTINFO)
       pi = (struct in_pktinfo *) CMSG_DATA(cm);
 
-    if (cm->cmsg_level == IPPROTO_IP && cm->cmsg_type == IP_TTL)
+    if (cm->cmsg_level == SOL_IP && cm->cmsg_type == IP_TTL)
       ttl = (int *) CMSG_DATA(cm);
   }
 
@@ -249,31 +228,28 @@ sysio_process_rx_cmsgs(sock *s, struct msghdr *msg)
   return;
 }
 
-/*
 static void
 sysio_prepare_tx_cmsgs(sock *s, struct msghdr *msg, void *cbuf, size_t cbuflen)
 {
   struct cmsghdr *cm;
   struct in_pktinfo *pi;
 
-  if (!(s->flags & SKF_LADDR_TX))
-    return;
-
   msg->msg_control = cbuf;
   msg->msg_controllen = cbuflen;
 
   cm = CMSG_FIRSTHDR(msg);
-  cm->cmsg_level = IPPROTO_IP;
+  cm->cmsg_level = SOL_IP;
   cm->cmsg_type = IP_PKTINFO;
   cm->cmsg_len = CMSG_LEN(sizeof(*pi));
 
   pi = (struct in_pktinfo *) CMSG_DATA(cm);
-  set_inaddr(&pi->ipi_spec_dst, s->saddr);
   pi->ipi_ifindex = s->iface ? s->iface->index : 0;
+  set_inaddr(&pi->ipi_spec_dst, s->saddr);
+  set_inaddr(&pi->ipi_addr, IPA_NONE);
 
   msg->msg_controllen = cm->cmsg_len;
 }
-*/
+
 
 #endif
 
@@ -292,7 +268,7 @@ sysio_prepare_tx_cmsgs(sock *s, struct msghdr *msg, void *cbuf, size_t cbuflen)
 static int
 sk_set_min_ttl4(sock *s, int ttl)
 {
-  if (setsockopt(s->fd, IPPROTO_IP, IP_MINTTL, &ttl, sizeof(ttl)) < 0)
+  if (setsockopt(s->fd, SOL_IP, IP_MINTTL, &ttl, sizeof(ttl)) < 0)
   {
     if (errno == ENOPROTOOPT)
       log(L_ERR "Kernel does not support IPv4 TTL security");
@@ -310,7 +286,7 @@ sk_set_min_ttl4(sock *s, int ttl)
 static int
 sk_set_min_ttl6(sock *s, int ttl)
 {
-  if (setsockopt(s->fd, IPPROTO_IPV6, IPV6_MINHOPCOUNT, &ttl, sizeof(ttl)) < 0)
+  if (setsockopt(s->fd, SOL_IPV6, IPV6_MINHOPCOUNT, &ttl, sizeof(ttl)) < 0)
   {
     if (errno == ENOPROTOOPT)
       log(L_ERR "Kernel does not support IPv6 TTL security");
diff --git a/sysdep/unix/io.c b/sysdep/unix/io.c
index 6e3f1e4d..428f24cc 100644
--- a/sysdep/unix/io.c
+++ b/sysdep/unix/io.c
@@ -23,6 +23,8 @@
 #include <fcntl.h>
 #include <errno.h>
 #include <netinet/in.h>
+#include <netinet/tcp.h>
+#include <netinet/udp.h>
 #include <netinet/icmp6.h>
 
 #include "nest/bird.h"
@@ -489,6 +491,11 @@ tm_format_datetime(char *x, struct timeformat *fmt_spec, bird_clock_t t)
 #define SOL_IPV6 IPPROTO_IPV6
 #endif
 
+#ifndef SOL_ICMPV6
+#define SOL_ICMPV6 IPPROTO_ICMPV6
+#endif
+
+
 static list sock_list;
 static struct birdsock *current_sock;
 static struct birdsock *stored_sock;
@@ -553,6 +560,43 @@ sk_free(resource *r)
 }
 
 void
+sk_set_rbsize(sock *s, uint val)
+{
+  ASSERT(s->rbuf_alloc == s->rbuf);
+
+  if (s->rbsize == val)
+    return;
+
+  s->rbsize = val;
+  xfree(s->rbuf_alloc);
+  s->rbuf_alloc = xmalloc(val);
+  s->rpos = s->rbuf = s->rbuf_alloc;
+}
+
+void
+sk_set_tbsize(sock *s, uint val)
+{
+  ASSERT(s->tbuf_alloc == s->tbuf);
+
+  if (s->tbsize == val)
+    return;
+
+  byte *old_tbuf = s->tbuf;
+
+  s->tbsize = val;
+  s->tbuf = s->tbuf_alloc = xrealloc(s->tbuf_alloc, val);
+  s->tpos = s->tbuf + (s->tpos - old_tbuf);
+  s->ttx  = s->tbuf + (s->ttx  - old_tbuf);
+}
+
+void
+sk_set_tbuf(sock *s, void *tbuf)
+{
+  s->tbuf = tbuf ?: s->tbuf_alloc;
+  s->ttx = s->tpos = s->tbuf;
+}
+
+void
 sk_reallocate(sock *s)
 {
   sk_free_bufs(s);
@@ -703,11 +747,11 @@ sysio_register_cmsgs(sock *s)
   int ok = 1;
 
   if ((s->flags & SKF_LADDR_RX) &&
-      (setsockopt(s->fd, IPPROTO_IPV6, IPV6_RECVPKTINFO, &ok, sizeof(ok)) < 0))
+      (setsockopt(s->fd, SOL_IPV6, IPV6_RECVPKTINFO, &ok, sizeof(ok)) < 0))
     return "IPV6_RECVPKTINFO";
 
   if ((s->flags & SKF_TTL_RX) &&
-      (setsockopt(s->fd, IPPROTO_IPV6, IPV6_RECVHOPLIMIT, &ok, sizeof(ok)) < 0))
+      (setsockopt(s->fd, SOL_IPV6, IPV6_RECVHOPLIMIT, &ok, sizeof(ok)) < 0))
     return "IPV6_RECVHOPLIMIT";
 
   return NULL;
@@ -722,10 +766,10 @@ sysio_process_rx_cmsgs(sock *s, struct msghdr *msg)
 
   for (cm = CMSG_FIRSTHDR(msg); cm != NULL; cm = CMSG_NXTHDR(msg, cm))
   {
-    if (cm->cmsg_level == IPPROTO_IPV6 && cm->cmsg_type == IPV6_PKTINFO)
+    if (cm->cmsg_level == SOL_IPV6 && cm->cmsg_type == IPV6_PKTINFO)
       pi = (struct in6_pktinfo *) CMSG_DATA(cm);
 
-    if (cm->cmsg_level == IPPROTO_IPV6 && cm->cmsg_type == IPV6_HOPLIMIT)
+    if (cm->cmsg_level == SOL_IPV6 && cm->cmsg_type == IPV6_HOPLIMIT)
       hlim = (int *) CMSG_DATA(cm);
   }
 
@@ -749,32 +793,27 @@ sysio_process_rx_cmsgs(sock *s, struct msghdr *msg)
   return;
 }
 
-/*
 static void
 sysio_prepare_tx_cmsgs(sock *s, struct msghdr *msg, void *cbuf, size_t cbuflen)
 {
   struct cmsghdr *cm;
   struct in6_pktinfo *pi;
 
-  if (!(s->flags & SKF_LADDR_TX))
-    return;
-
   msg->msg_control = cbuf;
   msg->msg_controllen = cbuflen;
 
   cm = CMSG_FIRSTHDR(msg);
-  cm->cmsg_level = IPPROTO_IPV6;
+  cm->cmsg_level = SOL_IPV6;
   cm->cmsg_type = IPV6_PKTINFO;
   cm->cmsg_len = CMSG_LEN(sizeof(*pi));
 
   pi = (struct in6_pktinfo *) CMSG_DATA(cm);
-  set_inaddr(&pi->ipi6_addr, s->saddr);
   pi->ipi6_ifindex = s->iface ? s->iface->index : 0;
+  set_inaddr(&pi->ipi6_addr, s->saddr);
 
   msg->msg_controllen = cm->cmsg_len;
-  return;
 }
-*/
+
 #endif
 
 static char *
@@ -786,11 +825,6 @@ sk_set_ttl_int(sock *s)
 #else
   if (setsockopt(s->fd, SOL_IP, IP_TTL, &s->ttl, sizeof(s->ttl)) < 0)
     return "IP_TTL";
-#ifdef CONFIG_UNIX_DONTROUTE
-  int one = 1;
-  if (s->ttl == 1 && setsockopt(s->fd, SOL_SOCKET, SO_DONTROUTE, &one, sizeof(one)) < 0)
-    return "SO_DONTROUTE";
-#endif 
 #endif
   return NULL;
 }
@@ -801,6 +835,7 @@ sk_set_ttl_int(sock *s)
 static char *
 sk_setup(sock *s)
 {
+  int one = 1;
   int fd = s->fd;
   char *err = NULL;
 
@@ -809,6 +844,41 @@ sk_setup(sock *s)
   if (s->type == SK_UNIX)
     return NULL;
 
+  if (ipa_nonzero(s->saddr) && !(s->flags & SKF_BIND))
+    s->flags |= SKF_PKTINFO;
+
+#ifdef CONFIG_USE_HDRINCL
+  if ((s->type == SK_IP) && (s->flags & SKF_PKTINFO))
+  {
+    s->flags &= ~SKF_PKTINFO;
+    s->flags |= SKF_HDRINCL;
+    if (setsockopt(fd, SOL_IP, IP_HDRINCL, &one, sizeof(one)) < 0)
+      ERR("IP_HDRINCL");
+  }
+#endif
+
+  if (s->iface)
+  {
+#ifdef SO_BINDTODEVICE
+    struct ifreq ifr;
+    strcpy(ifr.ifr_name, s->iface->name);
+    if (setsockopt(s->fd, SOL_SOCKET, SO_BINDTODEVICE, &ifr, sizeof(ifr)) < 0)
+      ERR("SO_BINDTODEVICE");
+#endif
+
+#ifdef CONFIG_UNIX_DONTROUTE
+    if (setsockopt(s->fd, SOL_SOCKET, SO_DONTROUTE, &one, sizeof(one)) < 0)
+      ERR("SO_DONTROUTE");
+#endif
+  }
+
+  if ((s->ttl >= 0) && (err = sk_set_ttl_int(s)))
+    goto bad;
+
+  if (err = sysio_register_cmsgs(s))
+    goto bad;
+
+
 #ifdef IPV6
   if ((s->tos >= 0) && setsockopt(fd, SOL_IPV6, IPV6_TCLASS, &s->tos, sizeof(s->tos)) < 0)
     WARN("IPV6_TCLASS");
@@ -821,15 +891,10 @@ sk_setup(sock *s)
     sk_set_priority(s, s->priority);
 
 #ifdef IPV6
-  int v = 1;
-  if ((s->flags & SKF_V6ONLY) && setsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY, &v, sizeof(v)) < 0)
+  if ((s->flags & SKF_V6ONLY) && setsockopt(fd, SOL_IPV6, IPV6_V6ONLY, &one, sizeof(one)) < 0)
     WARN("IPV6_V6ONLY");
 #endif
 
-  if ((s->ttl >= 0) && (err = sk_set_ttl_int(s)))
-    goto bad;
-
-  err = sysio_register_cmsgs(s);
 bad:
   return err;
 }
@@ -926,7 +991,7 @@ sk_set_broadcast(sock *s, int enable)
 int
 sk_set_ipv6_checksum(sock *s, int offset)
 {
-  if (setsockopt(s->fd, IPPROTO_IPV6, IPV6_CHECKSUM, &offset, sizeof(offset)) < 0)
+  if (setsockopt(s->fd, SOL_IPV6, IPV6_CHECKSUM, &offset, sizeof(offset)) < 0)
     {
       log(L_ERR "sk_set_ipv6_checksum: IPV6_CHECKSUM: %m");
       return -1;
@@ -945,7 +1010,7 @@ sk_set_icmp_filter(sock *s, int p1, int p2)
   ICMP6_FILTER_SETPASS(p1, &f);
   ICMP6_FILTER_SETPASS(p2, &f);
 
-  if (setsockopt(s->fd, IPPROTO_ICMPV6, ICMP6_FILTER, &f, sizeof(f)) < 0)
+  if (setsockopt(s->fd, SOL_ICMPV6, ICMP6_FILTER, &f, sizeof(f)) < 0)
     {
       log(L_ERR "sk_setup_icmp_filter: ICMP6_FILTER: %m");
       return -1;
@@ -961,7 +1026,7 @@ sk_setup_multicast(sock *s)
   int zero = 0;
   int index;
 
-  ASSERT(s->iface && s->iface->addr);
+  ASSERT(s->iface);
 
   index = s->iface->index;
   if (setsockopt(s->fd, SOL_IPV6, IPV6_MULTICAST_HOPS, &s->ttl, sizeof(s->ttl)) < 0)
@@ -971,9 +1036,6 @@ sk_setup_multicast(sock *s)
   if (setsockopt(s->fd, SOL_IPV6, IPV6_MULTICAST_IF, &index, sizeof(index)) < 0)
     ERR("IPV6_MULTICAST_IF");
 
-  if (err = sysio_bind_to_iface(s))
-    goto bad;
-
   return 0;
 
 bad:
@@ -981,18 +1043,17 @@ bad:
   return -1;
 }
 
+#ifdef CONFIG_IPV6_GLIBC_20
+#define ipv6mr_interface ipv6mr_ifindex
+#endif
+
 int
 sk_join_group(sock *s, ip_addr maddr)
 {
   struct ipv6_mreq mreq;
 
   set_inaddr(&mreq.ipv6mr_multiaddr, maddr);
-
-#ifdef CONFIG_IPV6_GLIBC_20
-  mreq.ipv6mr_ifindex = s->iface->index;
-#else
   mreq.ipv6mr_interface = s->iface->index;
-#endif
 
   if (setsockopt(s->fd, SOL_IPV6, IPV6_JOIN_GROUP, &mreq, sizeof(mreq)) < 0)
     {
@@ -1009,12 +1070,7 @@ sk_leave_group(sock *s, ip_addr maddr)
   struct ipv6_mreq mreq;
 	
   set_inaddr(&mreq.ipv6mr_multiaddr, maddr);
-
-#ifdef CONFIG_IPV6_GLIBC_20
-  mreq.ipv6mr_ifindex = s->iface->index;
-#else
   mreq.ipv6mr_interface = s->iface->index;
-#endif
 
   if (setsockopt(s->fd, SOL_IPV6, IPV6_LEAVE_GROUP, &mreq, sizeof(mreq)) < 0)
     {
@@ -1032,7 +1088,7 @@ sk_setup_multicast(sock *s)
 {
   char *err;
 
-  ASSERT(s->iface && s->iface->addr);
+  ASSERT(s->iface);
 
   if (err = sysio_setup_multicast(s))
     {
@@ -1142,31 +1198,45 @@ int
 sk_open(sock *s)
 {
   int fd;
-  sockaddr sa;
   int one = 1;
-  int type = s->type;
-  int has_src = ipa_nonzero(s->saddr) || s->sport;
+  int do_bind = 0;
+  int bind_port = 0;
+  ip_addr bind_addr = IPA_NONE;
+  sockaddr sa;
   char *err;
 
-  switch (type)
+  switch (s->type)
     {
     case SK_TCP_ACTIVE:
       s->ttx = "";			/* Force s->ttx != s->tpos */
       /* Fall thru */
     case SK_TCP_PASSIVE:
       fd = socket(BIRD_PF, SOCK_STREAM, IPPROTO_TCP);
+      bind_port = s->sport;
+      bind_addr = s->saddr;
+      do_bind = bind_port || ipa_nonzero(bind_addr);
       break;
+
     case SK_UDP:
       fd = socket(BIRD_PF, SOCK_DGRAM, IPPROTO_UDP);
+      bind_port = s->sport;
+      bind_addr = (s->flags & SKF_BIND) ? s->saddr : IPA_NONE;
+      do_bind = 1;
       break;
+
     case SK_IP:
       fd = socket(BIRD_PF, SOCK_RAW, s->dport);
+      bind_port = 0;
+      bind_addr = (s->flags & SKF_BIND) ? s->saddr : IPA_NONE;
+      do_bind = ipa_nonzero(bind_addr);
       break;
+
     case SK_MAGIC:
       fd = s->fd;
       break;
+
     default:
-      bug("sk_open() called for invalid sock type %d", type);
+      bug("sk_open() called for invalid sock type %d", s->type);
     }
   if (fd < 0)
     die("sk_open: socket: %m");
@@ -1175,31 +1245,28 @@ sk_open(sock *s)
   if (err = sk_setup(s))
     goto bad;
 
-  if (has_src)
+  if (do_bind)
     {
-      int port;
-
-      if (type == SK_IP)
-	port = 0;
-      else
+      if (bind_port)
 	{
-	  port = s->sport;
 	  if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one)) < 0)
 	    ERR("SO_REUSEADDR");
-	
+
 #ifdef CONFIG_NO_IFACE_BIND
 	  /* Workaround missing ability to bind to an iface */
-	  if ((type == SK_UDP) && s->iface && ipa_zero(s->saddr))
+	  if ((s->type == SK_UDP) && s->iface && ipa_zero(bind_addr))
 	  {
 	    if (setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &one, sizeof(one)) < 0)
 	      ERR("SO_REUSEPORT");
 	  }
 #endif
 	}
-      fill_in_sockaddr(&sa, s->saddr, s->iface, port);
+
+      fill_in_sockaddr(&sa, bind_addr, s->iface, bind_port);
       if (bind(fd, (struct sockaddr *) &sa, sizeof(sa)) < 0)
 	ERR("bind");
     }
+
   fill_in_sockaddr(&sa, s->daddr, s->iface, s->dport);
 
   if (s->password)
@@ -1209,7 +1276,7 @@ sk_open(sock *s)
 	goto bad_no_log;
     }
 
-  switch (type)
+  switch (s->type)
     {
     case SK_TCP_ACTIVE:
       if (connect(fd, (struct sockaddr *) &sa, sizeof(sa)) >= 0)
@@ -1287,6 +1354,79 @@ sk_open_unix(sock *s, char *name)
   die("Unable to create control socket %s", name);
 }
 
+
+static inline int
+sk_sendmsg(sock *s)
+{
+  struct iovec iov = {s->tbuf, s->tpos - s->tbuf};
+  byte cmsg_buf[CMSG_TX_SPACE];
+  sockaddr dst;
+
+  fill_in_sockaddr(&dst, s->daddr, s->iface, s->dport);
+
+  struct msghdr msg = {
+    .msg_name = &dst,
+    .msg_namelen = sizeof(dst),
+    .msg_iov = &iov,
+    .msg_iovlen = 1
+  };
+
+#ifdef CONFIG_USE_HDRINCL
+  byte hdr[20];
+  struct iovec iov2[2] = { {hdr, 20}, iov };
+
+  if (s->flags & SKF_HDRINCL)
+  {
+    fill_ip_header(s, hdr, iov.iov_len);
+    msg.msg_iov = iov2;
+    msg.msg_iovlen = 2;
+  }
+#endif
+
+  if (s->flags & SKF_PKTINFO)
+    sysio_prepare_tx_cmsgs(s, &msg, cmsg_buf, sizeof(cmsg_buf));
+
+  return sendmsg(s->fd, &msg, 0);
+}
+
+static inline int
+sk_recvmsg(sock *s)
+{
+  struct iovec iov = {s->rbuf, s->rbsize};
+  byte cmsg_buf[CMSG_RX_SPACE];
+  sockaddr src;
+
+  struct msghdr msg = {
+    .msg_name = &src,
+    .msg_namelen = sizeof(src),
+    .msg_iov = &iov,
+    .msg_iovlen = 1,
+    .msg_control = cmsg_buf,
+    .msg_controllen = sizeof(cmsg_buf),
+    .msg_flags = 0
+  };
+
+  int rv = recvmsg(s->fd, &msg, 0);
+  if (rv < 0)
+    return rv;
+
+  //ifdef IPV4
+  //  if (cf_type == SK_IP)
+  //    rv = ipv4_skip_header(pbuf, rv);
+  //endif
+
+  get_sockaddr(&src, &s->faddr, NULL, &s->fport, 1);
+  sysio_process_rx_cmsgs(s, &msg);
+
+  if (msg.msg_flags & MSG_TRUNC)
+    s->flags |= SKF_TRUNCATED;
+  else
+    s->flags &= ~SKF_TRUNCATED;
+
+  return rv;
+}
+
+
 static inline void reset_tx_buffer(sock *s) { s->ttx = s->tpos = s->tbuf; }
 
 static int
@@ -1323,20 +1463,7 @@ sk_maybe_write(sock *s)
 	if (s->tbuf == s->tpos)
 	  return 1;
 
-	sockaddr sa;
-	fill_in_sockaddr(&sa, s->daddr, s->iface, s->dport);
-
-	struct iovec iov = {s->tbuf, s->tpos - s->tbuf};
-	// byte cmsg_buf[CMSG_TX_SPACE];
-
-	struct msghdr msg = {
-	  .msg_name = &sa,
-	  .msg_namelen = sizeof(sa),
-	  .msg_iov = &iov,
-	  .msg_iovlen = 1};
-
-	// sysio_prepare_tx_cmsgs(s, &msg, cmsg_buf, sizeof(cmsg_buf));
-	e = sendmsg(s->fd, &msg, 0);
+	e = sk_sendmsg(s);
 
 	if (e < 0)
 	  {
@@ -1346,6 +1473,9 @@ sk_maybe_write(sock *s)
 		s->err_hook(s, errno);
 		return -1;
 	      }
+
+	    if (!s->tx_hook)
+	      reset_tx_buffer(s);
 	    return 0;
 	  }
 	reset_tx_buffer(s);
@@ -1408,12 +1538,15 @@ sk_send(sock *s, unsigned len)
  *
  * This is a sk_send() replacement for connection-less packet sockets
  * which allows destination of the packet to be chosen dynamically.
+ * Raw IP sockets should use 0 for @port.
  */
 int
 sk_send_to(sock *s, unsigned len, ip_addr addr, unsigned port)
 {
   s->daddr = addr;
-  s->dport = port;
+  if (port)
+    s->dport = port;
+
   s->ttx = s->tbuf;
   s->tpos = s->tbuf + len;
   return sk_maybe_write(s);
@@ -1480,22 +1613,9 @@ sk_read(sock *s)
       return s->rx_hook(s, 0);
     default:
       {
-	sockaddr sa;
 	int e;
 
-	struct iovec iov = {s->rbuf, s->rbsize};
-	byte cmsg_buf[CMSG_RX_SPACE];
-
-	struct msghdr msg = {
-	  .msg_name = &sa,
-	  .msg_namelen = sizeof(sa),
-	  .msg_iov = &iov,
-	  .msg_iovlen = 1,
-	  .msg_control = cmsg_buf,
-	  .msg_controllen = sizeof(cmsg_buf),
-	  .msg_flags = 0};
-
-	e = recvmsg(s->fd, &msg, 0);
+	e = sk_recvmsg(s);
 
 	if (e < 0)
 	  {
@@ -1503,10 +1623,8 @@ sk_read(sock *s)
 	      s->err_hook(s, errno);
 	    return 0;
 	  }
-	s->rpos = s->rbuf + e;
-	get_sockaddr(&sa, &s->faddr, NULL, &s->fport, 1);
-	sysio_process_rx_cmsgs(s, &msg);
 
+	s->rpos = s->rbuf + e;
 	s->rx_hook(s, e);
 	return 1;
       }