cvs commit: src/sys/netinet raw_ip.c

Gleb Smirnoff glebius at
Tue Mar 20 13:51:48 UTC 2007

On Tue, Mar 20, 2007 at 01:15:20PM +0000, Bruce M Simpson wrote:
B> bms         2007-03-20 13:15:20 UTC
B>   FreeBSD src repository
B>   Modified files:
B>     sys/netinet          raw_ip.c 
B>   Log:
B>   Increase default size of raw IP send and receive buffers to the same as
B>   udp_sendspace, to avoid a situation where jumbograms (datagrams > 9KB)
B>   are unnecessarily fragmented.
B>   A common use case for this is OSPF link-state database synchronization
B>   during adjacency bringup on a high speed network with a large MTU.
B>   It is not possible to auto-tune this setting until a socket is bound to
B>   a given interface, and because the laddr part of the inpcb tuple may be
B>   overridden, it makes no sense to do so. Applications may request a larger
B>   socket buffer size by using the SO_SENDBUF and SO_RECVBUF socket options.
B>   Certain applications such as Quagga ospfd do not probe for interface MTU
B>   and therefore do not increase SO_SENDBUF in this use case.
B>   XORP is not affected by this problem as it preemptively uses SO_SENDBUF
B>   and SO_RECVBUF to account for any possible additional latency in XRL IPC.

B> -u_long      rip_sendspace = RIPSNDQ;
B> -u_long      rip_recvspace = RIPRCVQ;
B> +u_long      rip_sendspace = 9216;
B> +u_long      rip_recvspace = 9216;

We've got interfaces with even larger MTU. Why shouldn't we permit sending
larger datagrams?

Totus tuus, Glebius.

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