Increase default size of raw IP send and receive buffers to the same as

udp_sendspace, to avoid a situation where jumbograms (datagrams > 9KB)
are unnecessarily fragmented.

A common use case for this is OSPF link-state database synchronization
during adjacency bringup on a high speed network with a large MTU.

It is not possible to auto-tune this setting until a socket is bound to
a given interface, and because the laddr part of the inpcb tuple may be
overridden, it makes no sense to do so. Applications may request a larger
socket buffer size by using the SO_SENDBUF and SO_RECVBUF socket options.

Certain applications such as Quagga ospfd do not probe for interface MTU
and therefore do not increase SO_SENDBUF in this use case.
XORP is not affected by this problem as it preemptively uses SO_SENDBUF
and SO_RECVBUF to account for any possible additional latency in XRL IPC.

PR:		kern/108375
Requested by:	Vladimir Ivanov
MFC after:	1 week

1 files changed, 2 insertions, 8 deletions

diff --git a/sys/netinet/raw_ip.c b/sys/netinet/raw_ip.c
index 51fe333..0c76d30 100644
--- a/sys/netinet/raw_ip.c
+++ b/sys/netinet/raw_ip.c
@@ -106,12 +106,6 @@ int (*ip_rsvp_vif)(struct socket *, struct sockopt *);
 void (*ip_rsvp_force_done)(struct socket *);
 
 /*
- * Nominal space allocated to a raw ip socket.
- */
-#define	RIPSNDQ		8192
-#define	RIPRCVQ		8192
-
-/*
  * Raw interface to IP protocol.
  */
 
@@ -595,8 +589,8 @@ rip_ctlinput(int cmd, struct sockaddr *sa, void *vip)
 	}
 }
 
-u_long	rip_sendspace = RIPSNDQ;
-u_long	rip_recvspace = RIPRCVQ;
+u_long	rip_sendspace = 9216;
+u_long	rip_recvspace = 9216;
 
 SYSCTL_ULONG(_net_inet_raw, OID_AUTO, maxdgram, CTLFLAG_RW,
     &rip_sendspace, 0, "Maximum outgoing raw IP datagram size");