On Wed, Nov 19, 2014 at 04:50:23PM +0100, Martin Pieuchot wrote:
> ...and in the end, they believe the mbuf(9) flags!
>
> There's no good reason to recheck if the IP destination address is a
> multicast or broadcast in {tcp,udp}_input(). We've already done that
> when the packet got delivered.
>
> So the diff below makes sure the multicast flag is set (jut be as
> paranoid as with broadcast) and check for these flags in the upper
> layer.
>
> I verified with crafted packets that this works, the goal of this diff
> is obviously to reduce the usage of "rcvif" pointers (and simplify
> in_broadcast() afterward).
>
> Comments, ok?
>
Ok
>
> Index: netinet/ip_input.c
> ===================================================================
> RCS file: /home/ncvs/src/sys/netinet/ip_input.c,v
> retrieving revision 1.241
> diff -u -p -r1.241 ip_input.c
> --- netinet/ip_input.c 5 Nov 2014 14:03:02 -0000 1.241
> +++ netinet/ip_input.c 19 Nov 2014 15:39:59 -0000
> @@ -348,6 +348,10 @@ ipv4_input(struct mbuf *m)
>
> if (IN_MULTICAST(ip->ip_dst.s_addr)) {
> struct in_multi *inm;
> +
> + /* Paranoia. */
> + m->m_flags |= M_MCAST;
> +
> #ifdef MROUTING
> if (ipmforwarding && ip_mrouter) {
> if (m->m_flags & M_EXT) {
> Index: netinet/tcp_input.c
> ===================================================================
> RCS file: /home/ncvs/src/sys/netinet/tcp_input.c,v
> retrieving revision 1.283
> diff -u -p -r1.283 tcp_input.c
> --- netinet/tcp_input.c 18 Nov 2014 02:37:31 -0000 1.283
> +++ netinet/tcp_input.c 19 Nov 2014 15:39:59 -0000
> @@ -394,7 +394,6 @@ tcp_input(struct mbuf *m, ...)
>
> /*
> * RFC1122 4.2.3.10, p. 104: discard bcast/mcast SYN
> - * See below for AF specific multicast.
> */
> if (m->m_flags & (M_BCAST|M_MCAST))
> goto drop;
> @@ -459,10 +458,6 @@ tcp_input(struct mbuf *m, ...)
> switch (af) {
> case AF_INET:
> ip = mtod(m, struct ip *);
> - if (IN_MULTICAST(ip->ip_dst.s_addr) ||
> - in_broadcast(ip->ip_dst, m->m_pkthdr.rcvif,
> - m->m_pkthdr.ph_rtableid))
> - goto drop;
> #ifdef TCP_ECN
> /* save ip_tos before clearing it for checksum */
> iptos = ip->ip_tos;
> Index: netinet/udp_usrreq.c
> ===================================================================
> RCS file: /home/ncvs/src/sys/netinet/udp_usrreq.c,v
> retrieving revision 1.191
> diff -u -p -r1.191 udp_usrreq.c
> --- netinet/udp_usrreq.c 9 Nov 2014 22:05:08 -0000 1.191
> +++ netinet/udp_usrreq.c 19 Nov 2014 15:39:59 -0000
> @@ -400,16 +400,7 @@ udp_input(struct mbuf *m, ...)
> }
> #endif
>
> -#ifdef INET6
> - if ((ip6 && IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) ||
> - (ip && IN_MULTICAST(ip->ip_dst.s_addr)) ||
> - (ip && in_broadcast(ip->ip_dst, m->m_pkthdr.rcvif,
> - m->m_pkthdr.ph_rtableid))) {
> -#else /* INET6 */
> - if (IN_MULTICAST(ip->ip_dst.s_addr) ||
> - in_broadcast(ip->ip_dst, m->m_pkthdr.rcvif,
> - m->m_pkthdr.ph_rtableid)) {
> -#endif /* INET6 */
> + if (m->m_flags & (M_BCAST|M_MCAST)) {
> struct inpcb *last;
> /*
> * Deliver a multicast or broadcast datagram to *all* sockets
> Index: netinet6/ip6_input.c
> ===================================================================
> RCS file: /home/ncvs/src/sys/netinet6/ip6_input.c,v
> retrieving revision 1.130
> diff -u -p -r1.130 ip6_input.c
> --- netinet6/ip6_input.c 14 Oct 2014 09:52:26 -0000 1.130
> +++ netinet6/ip6_input.c 19 Nov 2014 15:39:59 -0000
> @@ -398,6 +398,9 @@ ip6_input(struct mbuf *m)
> if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
> struct in6_multi *in6m = 0;
>
> + /* Paranoia. */
> + m->m_flags |= M_MCAST;
> +
> in6_ifstat_inc(ifp, ifs6_in_mcast);
> /*
> * See if we belong to the destination multicast group on the
>
--
:wq Claudio
