Date: Wed, 27 Oct 2004 12:28:22 -0700 From: Julian Elischer <julian@elischer.org> To: Bruce M Simpson <bms@spc.org> Cc: freebsd-net@freebsd.org Subject: Re: Implementing IP_SENDIF (like SO_BINDTODEVICE) Message-ID: <417FF6D6.4010201@elischer.org> In-Reply-To: <20041027073858.GC719@empiric.icir.org> References: <20041027073858.GC719@empiric.icir.org>
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Bruce M Simpson wrote:
>It annoys me that we have to resort to BPF to send IP datagrams on
>unnumbered interfaces. Here is a half baked idea. Please look and
>tell me what you think.
>
I've sent lots of datagrams on un-numberred interfaces using netgraph..
>
>
>------------------------------------------------------------------------
>
>Adding IP_SENDIF (like Linux's SO_BINDTODEVICE) support to FreeBSD.
>Clean up the RFC 1724 hack in ip_output.c
>
>TODO:
>
>Add IP_SENDIF processing to ip_ctloutput.
>Move inp_depend6.inp6_ifindex into general inpcb structure.
>Update #define.
>Pass IP_ROUTETOIF flag to ip_output() from udp and rawip.
>Pass inp_ifindex to ip_output() as destination from udp and rawip.
>
>Index: src/sys/netinet/ip_output.c
>===================================================================
>RCS file: /home/ncvs/src/sys/netinet/ip_output.c,v
>retrieving revision 1.225.2.4
>diff -u -p -r1.225.2.4 ip_output.c
>--- src/sys/netinet/ip_output.c 22 Sep 2004 19:23:38 -0000 1.225.2.4
>+++ src/sys/netinet/ip_output.c 27 Oct 2004 07:27:24 -0000
>@@ -93,7 +93,7 @@ SYSCTL_INT(_net_inet_ip, OID_AUTO, mbuf_
> #endif
>
> static struct mbuf *ip_insertoptions(struct mbuf *, struct mbuf *, int *);
>-static struct ifnet *ip_multicast_if(struct in_addr *, int *);
>+static struct ifnet *ina_to_rfc1724_if(struct in_addr *, int *);
> static void ip_mloopback
> (struct ifnet *, struct mbuf *, struct sockaddr_in *, int);
> static int ip_getmoptions
>@@ -206,19 +206,30 @@ again:
> dst->sin_addr = ip->ip_dst;
> }
> /*
>- * If routing to interface only,
>- * short circuit routing lookup.
>+ * If routing to interface only, short circuit routing lookup.
>+ *
>+ * Assume the destination is either the destination end of a
>+ * point-to-point interface, the network address of an interface,
>+ * or the address of an interface itself. In the last case, an
>+ * interface may be specified by index as per RFC 1724.
>+ *
> */
> if (flags & IP_ROUTETOIF) {
>- if ((ia = ifatoia(ifa_ifwithdstaddr(sintosa(dst)))) == NULL &&
>- (ia = ifatoia(ifa_ifwithnet(sintosa(dst)))) == NULL) {
>+ ia = ifatoia(ifa_ifwithdstaddr(sintosa(dst)));
>+ if (ia == NULL)
>+ ia = ifatoia(ifa_ifwithnet(sintosa(dst)));
>+ if (ia != NULL)
>+ ifp = ia->ia_ifp;
>+ else
>+ ifp = ina_to_rfc1724_if(&dst->sin_addr, NULL);
>+ if (ifp == NULL) {
> ipstat.ips_noroute++;
> error = ENETUNREACH;
> goto bad;
> }
>- ifp = ia->ia_ifp;
> ip->ip_ttl = 1;
>- isbroadcast = in_broadcast(dst->sin_addr, ifp);
>+ isbroadcast = (flags & IP_SENDONES) |
>+ in_broadcast(dst->sin_addr, ifp);
> } else if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr)) &&
> imo != NULL && imo->imo_multicast_ifp != NULL) {
> /*
>@@ -1531,11 +1542,15 @@ bad:
> * standard option (IP_TTL).
> */
>
>+#define INADDR_IFINDEX_MASK 0x00FFFFFF /* 0.0.0.0/8 */
>+
> /*
>- * following RFC1724 section 3.3, 0.0.0.0/8 is interpreted as interface index.
>+ * Look up the ifnet corresponding to a given IPv4 host address, taking the
>+ * RFC1724 hack into account. If the address given has the network prefix
>+ * 0.0.0.0/8, interpret the host portion as an interface index.
> */
> static struct ifnet *
>-ip_multicast_if(a, ifindexp)
>+ina_to_rfc1724_if(a, ifindexp)
> struct in_addr *a;
> int *ifindexp;
> {
>@@ -1544,8 +1559,8 @@ ip_multicast_if(a, ifindexp)
>
> if (ifindexp)
> *ifindexp = 0;
>- if (ntohl(a->s_addr) >> 24 == 0) {
>- ifindex = ntohl(a->s_addr) & 0xffffff;
>+ if ((ntohl(a->s_addr) & ~INADDR_IFINDEX_MASK) == 0) {
>+ ifindex = ntohl(a->s_addr) & 0x00FFFFFF;
> if (ifindex < 0 || if_index < ifindex)
> return NULL;
> ifp = ifnet_byindex(ifindex);
>@@ -1554,7 +1569,7 @@ ip_multicast_if(a, ifindexp)
> } else {
> INADDR_TO_IFP(*a, ifp);
> }
>- return ifp;
>+ return (ifp);
> }
>
> /*
>@@ -1634,7 +1649,7 @@ ip_setmoptions(sopt, imop)
> * it supports multicasting.
> */
> s = splimp();
>- ifp = ip_multicast_if(&addr, &ifindex);
>+ ifp = ina_to_rfc1724_if(&addr, &ifindex);
> if (ifp == NULL || (ifp->if_flags & IFF_MULTICAST) == 0) {
> splx(s);
> error = EADDRNOTAVAIL;
>@@ -1731,7 +1746,7 @@ ip_setmoptions(sopt, imop)
> RTFREE(ro.ro_rt);
> }
> else {
>- ifp = ip_multicast_if(&mreq.imr_interface, NULL);
>+ ifp = ina_to_rfc1724_if(&mreq.imr_interface, NULL);
> }
>
> /*
>@@ -1799,7 +1814,7 @@ ip_setmoptions(sopt, imop)
> if (mreq.imr_interface.s_addr == INADDR_ANY)
> ifp = NULL;
> else {
>- ifp = ip_multicast_if(&mreq.imr_interface, NULL);
>+ ifp = ina_to_rfc1724_if(&mreq.imr_interface, NULL);
> if (ifp == NULL) {
> error = EADDRNOTAVAIL;
> splx(s);
>
>
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