[src/trunk]: src/sys/netinet allow IP_MULTICAST_IF and IP_ADD/DROP_MEMBERSHIP...

[itojun <itojun%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/2e1047c848c4
branches:  trunk
changeset: 502180:2e1047c848c4
user:      itojun <itojun%NetBSD.org@localhost>
date:      Sat Jan 13 07:19:33 2001 +0000

description:
allow IP_MULTICAST_IF and IP_ADD/DROP_MEMBERSHIP to specify interface
by interface index.  if the interface address specified is in 0.0.0.0/8
it will be considered as interface index in network byteorder.

getsockopt(IP_MULTICAST_IF) preserves old behavior if
setsockopt(IP_MULTICAST_IF) was done with interface address, and
returns interface index if setsockopt(IP_MULTICAST_IF) was done with
interface index (again using the form in 0.0.0.0/8).

Suggested by Dave Thaler, based on RIPv2 MIB spec (RFC1724 section 3.3).

http://mail-index.netbsd.org/tech-net/2001/01/13/0003.html

diffstat:

 sys/netinet/ip_output.c |  46 +++++++++++++++++++++++++++++++++++++++++-----
 sys/netinet/ip_var.h    |   3 ++-
 2 files changed, 43 insertions(+), 6 deletions(-)

diffs (131 lines):

diff -r 075fe38b7ad2 -r 2e1047c848c4 sys/netinet/ip_output.c
--- a/sys/netinet/ip_output.c   Sat Jan 13 06:01:18 2001 +0000
+++ b/sys/netinet/ip_output.c   Sat Jan 13 07:19:33 2001 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: ip_output.c,v 1.80 2001/01/13 06:01:18 itojun Exp $    */
+/*     $NetBSD: ip_output.c,v 1.81 2001/01/13 07:19:33 itojun Exp $    */
 
 /*
  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
@@ -143,6 +143,7 @@
 #endif /*IPSEC*/
 
 static struct mbuf *ip_insertoptions __P((struct mbuf *, struct mbuf *, int *));
+static struct ifnet *ip_multicast_if __P((struct in_addr *, int *));
 static void ip_mloopback
        __P((struct ifnet *, struct mbuf *, struct sockaddr_in *));
 
@@ -1197,6 +1198,32 @@
 }
 
 /*
+ * following RFC1724 section 3.3, 0.0.0.0/8 is interpreted as interface index.
+ */
+static struct ifnet *
+ip_multicast_if(a, ifindexp)
+       struct in_addr *a;
+       int *ifindexp;
+{
+       int ifindex;
+       struct ifnet *ifp;
+
+       if (ifindexp)
+               *ifindexp = 0;
+       if (ntohl(a->s_addr) >> 24 == 0) {
+               ifindex = ntohl(a->s_addr) & 0xffffff;
+               if (ifindex < 0 || if_index < ifindex)
+                       return NULL;
+               ifp = ifindex2ifnet[ifindex];
+               if (ifindexp)
+                       *ifindexp = ifindex;
+       } else {
+               INADDR_TO_IFP(*a, ifp);
+       }
+       return ifp;
+}
+
+/*
  * Set the IP multicast options in response to user setsockopt().
  */
 int
@@ -1214,6 +1241,7 @@
        struct ip_moptions *imo = *imop;
        struct route ro;
        struct sockaddr_in *dst;
+       int ifindex;
 
        if (imo == NULL) {
                /*
@@ -1227,6 +1255,7 @@
                        return (ENOBUFS);
                *imop = imo;
                imo->imo_multicast_ifp = NULL;
+               imo->imo_multicast_addr.s_addr = INADDR_ANY;
                imo->imo_multicast_ttl = IP_DEFAULT_MULTICAST_TTL;
                imo->imo_multicast_loop = IP_DEFAULT_MULTICAST_LOOP;
                imo->imo_num_memberships = 0;
@@ -1257,12 +1286,16 @@
                 * IP address.  Find the interface and confirm that
                 * it supports multicasting.
                 */
-               INADDR_TO_IFP(addr, ifp);
+               ifp = ip_multicast_if(&addr, &ifindex);
                if (ifp == NULL || (ifp->if_flags & IFF_MULTICAST) == 0) {
                        error = EADDRNOTAVAIL;
                        break;
                }
                imo->imo_multicast_ifp = ifp;
+               if (ifindex)
+                       imo->imo_multicast_addr = addr;
+               else
+                       imo->imo_multicast_addr.s_addr = INADDR_ANY;
                break;
 
        case IP_MULTICAST_TTL:
@@ -1322,7 +1355,7 @@
                        ifp = ro.ro_rt->rt_ifp;
                        rtfree(ro.ro_rt);
                } else {
-                       INADDR_TO_IFP(mreq->imr_interface, ifp);
+                       ifp = ip_multicast_if(&mreq->imr_interface, NULL);
                }
                /*
                 * See if we found an interface, and confirm that it
@@ -1383,7 +1416,7 @@
                if (in_nullhost(mreq->imr_interface))
                        ifp = NULL;
                else {
-                       INADDR_TO_IFP(mreq->imr_interface, ifp);
+                       ifp = ip_multicast_if(&mreq->imr_interface, NULL);
                        if (ifp == NULL) {
                                error = EADDRNOTAVAIL;
                                break;
@@ -1458,7 +1491,10 @@
                (*mp)->m_len = sizeof(struct in_addr);
                if (imo == NULL || imo->imo_multicast_ifp == NULL)
                        *addr = zeroin_addr;
-               else {
+               else if (imo->imo_multicast_addr.s_addr) {
+                       /* return the value user has set */
+                       *addr = imo->imo_multicast_addr;
+               } else {
                        IFP_TO_IA(imo->imo_multicast_ifp, ia);
                        *addr = ia ? ia->ia_addr.sin_addr : zeroin_addr;
                }
diff -r 075fe38b7ad2 -r 2e1047c848c4 sys/netinet/ip_var.h
--- a/sys/netinet/ip_var.h      Sat Jan 13 06:01:18 2001 +0000
+++ b/sys/netinet/ip_var.h      Sat Jan 13 07:19:33 2001 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: ip_var.h,v 1.43 2000/10/17 02:57:01 thorpej Exp $      */
+/*     $NetBSD: ip_var.h,v 1.44 2001/01/13 07:19:33 itojun Exp $       */
 
 /*
  * Copyright (c) 1982, 1986, 1993
@@ -117,6 +117,7 @@
  */
 struct ip_moptions {
        struct    ifnet *imo_multicast_ifp; /* ifp for outgoing multicasts */
+       struct in_addr imo_multicast_addr; /* ifindex/addr on MULTICAST_IF */
        u_int8_t  imo_multicast_ttl;    /* TTL for outgoing multicasts */
        u_int8_t  imo_multicast_loop;   /* 1 => hear sends if a member */
        u_int16_t imo_num_memberships;  /* no. memberships this socket */