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

2 files changed, 26 insertions, 9 deletions

diff --git a/lib/resource.c b/lib/resource.c
index bf4b3ae9..64f9a39c 100644
--- a/lib/resource.c
+++ b/lib/resource.c
@@ -157,13 +157,13 @@ rfree(void *res)
 {
   resource *r = res;
 
-  if (r)
-    {
-      if (r->n.next)
-	rem_node(&r->n);
-      r->class->free(r);
-      xfree(r);
-    }
+  if (!r)
+    return;
+
+  if (r->n.next)
+    rem_node(&r->n);
+  r->class->free(r);
+  xfree(r);
 }
 
 /**
@@ -408,6 +408,9 @@ mb_realloc(void *m, unsigned size)
 void
 mb_free(void *m)
 {
+  if (!m)
+    return;
+
   struct mblock *b = SKIP_BACK(struct mblock, data, m);
   rfree(b);
 }
diff --git a/lib/socket.h b/lib/socket.h
index 780d596b..894d5561 100644
--- a/lib/socket.h
+++ b/lib/socket.h
@@ -57,6 +57,9 @@ int sk_open(sock *);			/* Open socket */
 int sk_send(sock *, unsigned len);	/* Send data, <0=err, >0=ok, 0=sleep */
 int sk_send_to(sock *, unsigned len, ip_addr to, unsigned port); /* sk_send to given destination */
 void sk_reallocate(sock *);		/* Free and allocate tbuf & rbuf */
+void sk_set_rbsize(sock *s, uint val);	/* Resize RX buffer */
+void sk_set_tbsize(sock *s, uint val);	/* Resize TX buffer, keeping content */
+void sk_set_tbuf(sock *s, void *tbuf);	/* Switch TX buffer, NULL-> return to internal */
 void sk_dump_all(void);
 int sk_set_ttl(sock *s, int ttl);	/* Set transmit TTL for given socket */
 int sk_set_min_ttl(sock *s, int ttl);	/* Set minimal accepted TTL for given socket */
@@ -89,10 +92,13 @@ extern int sk_priority_control;	/* Suggested priority for control traffic, shoul
 
 #define SKF_V6ONLY	1	/* Use IPV6_V6ONLY socket option */
 #define SKF_LADDR_RX	2	/* Report local address for RX packets */
-#define SKF_LADDR_TX	4	/* Allow to specify local address for TX packets */
-#define SKF_TTL_RX	8	/* Report TTL / Hop Limit for RX packets */
+#define SKF_TTL_RX	4	/* Report TTL / Hop Limit for RX packets */
+#define SKF_BIND	8	/* Bind datagram socket to given source address */
 
 #define SKF_THREAD	0x100	/* Socked used in thread, Do not add to main loop */
+#define SKF_TRUNCATED	0x200	/* Received packet was truncated, set by IO layer */
+#define SKF_HDRINCL	0x400	/* Used internally */
+#define SKF_PKTINFO	0x800	/* Used internally */
 
 /*
  *	Socket types		     SA SP DA DP IF  TTL SendTo	(?=may, -=must not, *=must)
@@ -118,6 +124,14 @@ extern int sk_priority_control;	/* Suggested priority for control traffic, shoul
  *  call sk_setup_multicast() to enable multicast on that socket,
  *  and then use sk_join_group() and sk_leave_group() to manage
  *  a set of received multicast groups.
+ *
+ *  For datagram (SK_UDP, SK_IP) sockets, there are two ways to handle
+ *  source address. The socket could be bound to it using bind()
+ *  syscall, but that also forbids the reception of multicast packets,
+ *  or the address could be set on per-packet basis using platform
+ *  dependent options (but these are not available in some corner
+ *  cases). The first way is used when SKF_BIND is specified, the
+ *  second way is used otherwise.
  */
 
 #endif