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Don't check for broadcast IPs on non-bcast pkts

Browse source 
in_broadcast() can be quite expensive, so skip calling it if the
incoming mbuf wasn't sent to a broadcast L2 address in the first
place.

Reviewed by: gnn
MFC after: 2 months
Sponsored by: EMC / Isilon Storage Division
Differential Revision: https://reviews.freebsd.org/D7309
This commit is contained in:
Ryan Stone 2016-08-18 22:59:05 +00:00
parent 90cc51a1ab
commit 41029db13f
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=304436
2 changed files with 15 additions and 1 deletions
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8
UPDATING
View file

@ -31,6 +31,14 @@ NOTE TO PEOPLE WHO THINK THAT FreeBSD 12.x IS SLOW:
disable the most expensive debugging functionality run
"ln -s 'abort:false,junk:false' /etc/malloc.conf".)
20160818:
The UDP receive code has been updated to only treat incoming UDP
packets that were addressed to an L2 broadcast address as L3
broadcast packets. It is not expected that this will affect any
standards-conforming UDP application. The new behaviour can be
disabled by setting the sysctl net.inet.udp.require_l2_bcast to
0.
20160818:
Remove the openbsd_poll system call.
__FreeBSD_version has been bumped because of this.

8
sys/netinet/udp_usrreq.c
View file

@ -126,6 +126,11 @@ SYSCTL_INT(_net_inet_udp, OID_AUTO, blackhole, CTLFLAG_VNET | CTLFLAG_RW,
&VNET_NAME(udp_blackhole), 0,
"Do not send port unreachables for refused connects");
static VNET_DEFINE(int, udp_require_l2_bcast) = 1;
SYSCTL_INT(_net_inet_udp, OID_AUTO, require_l2_bcast, CTLFLAG_VNET | CTLFLAG_RW,
&VNET_NAME(udp_require_l2_bcast), 0,
"Only treat packets sent to an L2 broadcast address as broadcast packets");
u_long udp_sendspace = 9216; /* really max datagram size */
SYSCTL_ULONG(_net_inet_udp, UDPCTL_MAXDGRAM, maxdgram, CTLFLAG_RW,
&udp_sendspace, 0, "Maximum outgoing UDP datagram size");
@ -523,7 +528,8 @@ udp_input(struct mbuf **mp, int *offp, int proto)
pcbinfo = udp_get_inpcbinfo(proto);
if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr)) ||
in_broadcast(ip->ip_dst, ifp)) {
((!VNET_NAME(udp_require_l2_bcast) || m->m_flags & M_BCAST) &&
in_broadcast(ip->ip_dst, ifp))) {
struct inpcb *last;
struct inpcbhead *pcblist;
struct ip_moptions *imo;