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NetBSD/sys/netinet/ip_output.c
mrg a5f00f16bc move the packet filter hooks in to a saner location. while i'm here, rename 
PACKET_FILTER to PFIL_HOOKS.
1996-09-14 14:40:20 +00:00

1108 lines
26 KiB
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/* $NetBSD: ip_output.c,v 1.32 1996/09/14 14:40:27 mrg Exp $ */
/*
* Copyright (c) 1982, 1986, 1988, 1990, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)ip_output.c 8.3 (Berkeley) 1/21/94
*/
#include <sys/param.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/errno.h>
#include <sys/protosw.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/systm.h>
#include <net/if.h>
#include <net/route.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/in_pcb.h>
#include <netinet/in_var.h>
#include <netinet/ip_var.h>
#ifdef PFIL_HOOKS
#include <net/pfil.h>
#endif /* PFIL_HOOKS */
#ifdef vax
#include <machine/mtpr.h>
#endif
#include <machine/stdarg.h>
static struct mbuf *ip_insertoptions __P((struct mbuf *, struct mbuf *, int *));
static void ip_mloopback
__P((struct ifnet *, struct mbuf *, struct sockaddr_in *));
/*
* IP output. The packet in mbuf chain m contains a skeletal IP
* header (with len, off, ttl, proto, tos, src, dst).
* The mbuf chain containing the packet will be freed.
* The mbuf opt, if present, will not be freed.
*/
int
#if __STDC__
ip_output(struct mbuf *m0, ...)
#else
ip_output(m0, va_alist)
struct mbuf *m0;
va_dcl
#endif
{
register struct ip *ip, *mhip;
register struct ifnet *ifp;
register struct mbuf *m = m0;
register int hlen = sizeof (struct ip);
int len, off, error = 0;
struct route iproute;
struct sockaddr_in *dst;
struct in_ifaddr *ia;
struct mbuf *opt;
struct route *ro;
int flags;
struct ip_moptions *imo;
va_list ap;
#ifdef PFIL_HOOKS
struct packet_filter_hook *pfh;
struct mbuf *m1;
#endif /* PFIL_HOOKS */
va_start(ap, m0);
opt = va_arg(ap, struct mbuf *);
ro = va_arg(ap, struct route *);
flags = va_arg(ap, int);
imo = va_arg(ap, struct ip_moptions *);
va_end(ap);
#ifdef DIAGNOSTIC
if ((m->m_flags & M_PKTHDR) == 0)
panic("ip_output no HDR");
#endif
if (opt) {
m = ip_insertoptions(m, opt, &len);
hlen = len;
}
ip = mtod(m, struct ip *);
/*
* Fill in IP header.
*/
if ((flags & (IP_FORWARDING|IP_RAWOUTPUT)) == 0) {
ip->ip_v = IPVERSION;
ip->ip_off &= IP_DF;
ip->ip_id = htons(ip_id++);
ip->ip_hl = hlen >> 2;
ipstat.ips_localout++;
} else {
hlen = ip->ip_hl << 2;
}
/*
* Route packet.
*/
if (ro == 0) {
ro = &iproute;
bzero((caddr_t)ro, sizeof (*ro));
}
dst = satosin(&ro->ro_dst);
/*
* If there is a cached route,
* check that it is to the same destination
* and is still up. If not, free it and try again.
*/
if (ro->ro_rt && ((ro->ro_rt->rt_flags & RTF_UP) == 0 ||
!in_hosteq(dst->sin_addr, ip->ip_dst))) {
RTFREE(ro->ro_rt);
ro->ro_rt = (struct rtentry *)0;
}
if (ro->ro_rt == 0) {
dst->sin_family = AF_INET;
dst->sin_len = sizeof(*dst);
dst->sin_addr = ip->ip_dst;
}
/*
* If routing to interface only,
* short circuit routing lookup.
*/
if (flags & IP_ROUTETOIF) {
if ((ia = ifatoia(ifa_ifwithladdr(sintosa(dst)))) == 0) {
ipstat.ips_noroute++;
error = ENETUNREACH;
goto bad;
}
ifp = ia->ia_ifp;
ip->ip_ttl = 1;
} else {
if (ro->ro_rt == 0)
rtalloc(ro);
if (ro->ro_rt == 0) {
ipstat.ips_noroute++;
error = EHOSTUNREACH;
goto bad;
}
ia = ifatoia(ro->ro_rt->rt_ifa);
ifp = ro->ro_rt->rt_ifp;
ro->ro_rt->rt_use++;
if (ro->ro_rt->rt_flags & RTF_GATEWAY)
dst = satosin(ro->ro_rt->rt_gateway);
}
if (IN_MULTICAST(ip->ip_dst.s_addr)) {
struct in_multi *inm;
m->m_flags |= M_MCAST;
/*
* IP destination address is multicast. Make sure "dst"
* still points to the address in "ro". (It may have been
* changed to point to a gateway address, above.)
*/
dst = satosin(&ro->ro_dst);
/*
* See if the caller provided any multicast options
*/
if (imo != NULL) {
ip->ip_ttl = imo->imo_multicast_ttl;
if (imo->imo_multicast_ifp != NULL)
ifp = imo->imo_multicast_ifp;
} else
ip->ip_ttl = IP_DEFAULT_MULTICAST_TTL;
/*
* Confirm that the outgoing interface supports multicast.
*/
if ((ifp->if_flags & IFF_MULTICAST) == 0) {
ipstat.ips_noroute++;
error = ENETUNREACH;
goto bad;
}
/*
* If source address not specified yet, use address
* of outgoing interface.
*/
if (in_nullhost(ip->ip_src)) {
register struct in_ifaddr *ia;
for (ia = in_ifaddr.tqh_first; ia; ia = ia->ia_list.tqe_next)
if (ia->ia_ifp == ifp) {
ip->ip_src = ia->ia_addr.sin_addr;
break;
}
}
IN_LOOKUP_MULTI(ip->ip_dst, ifp, inm);
if (inm != NULL &&
(imo == NULL || imo->imo_multicast_loop)) {
/*
* If we belong to the destination multicast group
* on the outgoing interface, and the caller did not
* forbid loopback, loop back a copy.
*/
ip_mloopback(ifp, m, dst);
}
#ifdef MROUTING
else {
/*
* If we are acting as a multicast router, perform
* multicast forwarding as if the packet had just
* arrived on the interface to which we are about
* to send. The multicast forwarding function
* recursively calls this function, using the
* IP_FORWARDING flag to prevent infinite recursion.
*
* Multicasts that are looped back by ip_mloopback(),
* above, will be forwarded by the ip_input() routine,
* if necessary.
*/
extern struct socket *ip_mrouter;
if (ip_mrouter && (flags & IP_FORWARDING) == 0) {
if (ip_mforward(m, ifp) != 0) {
m_freem(m);
goto done;
}
}
}
#endif
/*
* Multicasts with a time-to-live of zero may be looped-
* back, above, but must not be transmitted on a network.
* Also, multicasts addressed to the loopback interface
* are not sent -- the above call to ip_mloopback() will
* loop back a copy if this host actually belongs to the
* destination group on the loopback interface.
*/
if (ip->ip_ttl == 0 || (ifp->if_flags & IFF_LOOPBACK) != 0) {
m_freem(m);
goto done;
}
goto sendit;
}
#ifndef notdef
/*
* If source address not specified yet, use address
* of outgoing interface.
*/
if (in_nullhost(ip->ip_src))
ip->ip_src = ia->ia_addr.sin_addr;
#endif
/*
* Look for broadcast address and
* and verify user is allowed to send
* such a packet.
*/
if (in_broadcast(dst->sin_addr, ifp)) {
if ((ifp->if_flags & IFF_BROADCAST) == 0) {
error = EADDRNOTAVAIL;
goto bad;
}
if ((flags & IP_ALLOWBROADCAST) == 0) {
error = EACCES;
goto bad;
}
/* don't allow broadcast messages to be fragmented */
if ((u_int16_t)ip->ip_len > ifp->if_mtu) {
error = EMSGSIZE;
goto bad;
}
m->m_flags |= M_BCAST;
} else
m->m_flags &= ~M_BCAST;
#ifdef PFIL_HOOKS
/*
* Run through list of hooks for output packets.
*/
m1 = m;
for (pfh = pfil_hook_get(PFIL_OUT); pfh; pfh = pfh->pfil_link.le_next)
if (pfh->pfil_func) {
if (pfh->pfil_func(ip, hlen, m->m_pkthdr.rcvif, 1, &m1)) {
error = EHOSTUNREACH;
goto bad;
}
ip = mtod(m = m1, struct ip *);
}
#endif /* PFIL_HOOKS */
sendit:
/*
* If small enough for interface, can just send directly.
*/
if ((u_int16_t)ip->ip_len <= ifp->if_mtu) {
ip->ip_len = htons((u_int16_t)ip->ip_len);
ip->ip_off = htons((u_int16_t)ip->ip_off);
ip->ip_sum = 0;
ip->ip_sum = in_cksum(m, hlen);
error = (*ifp->if_output)(ifp, m, sintosa(dst), ro->ro_rt);
goto done;
}
/*
* Too large for interface; fragment if possible.
* Must be able to put at least 8 bytes per fragment.
*/
if (ip->ip_off & IP_DF) {
error = EMSGSIZE;
ipstat.ips_cantfrag++;
goto bad;
}
len = (ifp->if_mtu - hlen) &~ 7;
if (len < 8) {
error = EMSGSIZE;
goto bad;
}
{
int mhlen, firstlen = len;
struct mbuf **mnext = &m->m_nextpkt;
/*
* Loop through length of segment after first fragment,
* make new header and copy data of each part and link onto chain.
*/
m0 = m;
mhlen = sizeof (struct ip);
for (off = hlen + len; off < (u_int16_t)ip->ip_len; off += len) {
MGETHDR(m, M_DONTWAIT, MT_HEADER);
if (m == 0) {
error = ENOBUFS;
ipstat.ips_odropped++;
goto sendorfree;
}
*mnext = m;
mnext = &m->m_nextpkt;
m->m_data += max_linkhdr;
mhip = mtod(m, struct ip *);
*mhip = *ip;
if (hlen > sizeof (struct ip)) {
mhlen = ip_optcopy(ip, mhip) + sizeof (struct ip);
mhip->ip_hl = mhlen >> 2;
}
m->m_len = mhlen;
mhip->ip_off = ((off - hlen) >> 3) + (ip->ip_off & ~IP_MF);
if (ip->ip_off & IP_MF)
mhip->ip_off |= IP_MF;
if (off + len >= (u_int16_t)ip->ip_len)
len = (u_int16_t)ip->ip_len - off;
else
mhip->ip_off |= IP_MF;
mhip->ip_len = htons((u_int16_t)(len + mhlen));
m->m_next = m_copy(m0, off, len);
if (m->m_next == 0) {
error = ENOBUFS; /* ??? */
ipstat.ips_odropped++;
goto sendorfree;
}
m->m_pkthdr.len = mhlen + len;
m->m_pkthdr.rcvif = (struct ifnet *)0;
mhip->ip_off = htons((u_int16_t)mhip->ip_off);
mhip->ip_sum = 0;
mhip->ip_sum = in_cksum(m, mhlen);
ipstat.ips_ofragments++;
}
/*
* Update first fragment by trimming what's been copied out
* and updating header, then send each fragment (in order).
*/
m = m0;
m_adj(m, hlen + firstlen - (u_int16_t)ip->ip_len);
m->m_pkthdr.len = hlen + firstlen;
ip->ip_len = htons((u_int16_t)m->m_pkthdr.len);
ip->ip_off = htons((u_int16_t)(ip->ip_off | IP_MF));
ip->ip_sum = 0;
ip->ip_sum = in_cksum(m, hlen);
sendorfree:
for (m = m0; m; m = m0) {
m0 = m->m_nextpkt;
m->m_nextpkt = 0;
if (error == 0)
error = (*ifp->if_output)(ifp, m, sintosa(dst),
ro->ro_rt);
else
m_freem(m);
}
if (error == 0)
ipstat.ips_fragmented++;
}
done:
if (ro == &iproute && (flags & IP_ROUTETOIF) == 0 && ro->ro_rt) {
RTFREE(ro->ro_rt);
ro->ro_rt = 0;
}
return (error);
bad:
#ifdef PFIL_HOOKS
m1 = m;
for (pfh = pfil_hook_get(PFIL_BAD); pfh; pfh = pfh->pfil_link.le_next)
if (pfh->pfil_func) {
(void)pfh->pfil_func(ip, hlen, m->m_pkthdr.rcvif, 2, &m1);
ip = mtod(m = m1, struct ip *);
}
#endif /* PFIL_HOOKS */
m_freem(m0);
goto done;
}
/*
* Insert IP options into preformed packet.
* Adjust IP destination as required for IP source routing,
* as indicated by a non-zero in_addr at the start of the options.
*/
static struct mbuf *
ip_insertoptions(m, opt, phlen)
register struct mbuf *m;
struct mbuf *opt;
int *phlen;
{
register struct ipoption *p = mtod(opt, struct ipoption *);
struct mbuf *n;
register struct ip *ip = mtod(m, struct ip *);
unsigned optlen;
optlen = opt->m_len - sizeof(p->ipopt_dst);
if (optlen + (u_int16_t)ip->ip_len > IP_MAXPACKET)
return (m); /* XXX should fail */
if (!in_nullhost(p->ipopt_dst))
ip->ip_dst = p->ipopt_dst;
if (m->m_flags & M_EXT || m->m_data - optlen < m->m_pktdat) {
MGETHDR(n, M_DONTWAIT, MT_HEADER);
if (n == 0)
return (m);
n->m_pkthdr.len = m->m_pkthdr.len + optlen;
m->m_len -= sizeof(struct ip);
m->m_data += sizeof(struct ip);
n->m_next = m;
m = n;
m->m_len = optlen + sizeof(struct ip);
m->m_data += max_linkhdr;
bcopy((caddr_t)ip, mtod(m, caddr_t), sizeof(struct ip));
} else {
m->m_data -= optlen;
m->m_len += optlen;
m->m_pkthdr.len += optlen;
ovbcopy((caddr_t)ip, mtod(m, caddr_t), sizeof(struct ip));
}
ip = mtod(m, struct ip *);
bcopy((caddr_t)p->ipopt_list, (caddr_t)(ip + 1), (unsigned)optlen);
*phlen = sizeof(struct ip) + optlen;
ip->ip_len += optlen;
return (m);
}
/*
* Copy options from ip to jp,
* omitting those not copied during fragmentation.
*/
int
ip_optcopy(ip, jp)
struct ip *ip, *jp;
{
register u_char *cp, *dp;
int opt, optlen, cnt;
cp = (u_char *)(ip + 1);
dp = (u_char *)(jp + 1);
cnt = (ip->ip_hl << 2) - sizeof (struct ip);
for (; cnt > 0; cnt -= optlen, cp += optlen) {
opt = cp[0];
if (opt == IPOPT_EOL)
break;
if (opt == IPOPT_NOP) {
/* Preserve for IP mcast tunnel's LSRR alignment. */
*dp++ = IPOPT_NOP;
optlen = 1;
continue;
} else
optlen = cp[IPOPT_OLEN];
/* bogus lengths should have been caught by ip_dooptions */
if (optlen > cnt)
optlen = cnt;
if (IPOPT_COPIED(opt)) {
bcopy((caddr_t)cp, (caddr_t)dp, (unsigned)optlen);
dp += optlen;
}
}
for (optlen = dp - (u_char *)(jp+1); optlen & 0x3; optlen++)
*dp++ = IPOPT_EOL;
return (optlen);
}
/*
* IP socket option processing.
*/
int
ip_ctloutput(op, so, level, optname, mp)
int op;
struct socket *so;
int level, optname;
struct mbuf **mp;
{
register struct inpcb *inp = sotoinpcb(so);
register struct mbuf *m = *mp;
register int optval = 0;
int error = 0;
if (level != IPPROTO_IP) {
error = EINVAL;
if (op == PRCO_SETOPT && *mp)
(void) m_free(*mp);
} else switch (op) {
case PRCO_SETOPT:
switch (optname) {
case IP_OPTIONS:
#ifdef notyet
case IP_RETOPTS:
return (ip_pcbopts(optname, &inp->inp_options, m));
#else
return (ip_pcbopts(&inp->inp_options, m));
#endif
case IP_TOS:
case IP_TTL:
case IP_RECVOPTS:
case IP_RECVRETOPTS:
case IP_RECVDSTADDR:
if (m == NULL || m->m_len != sizeof(int))
error = EINVAL;
else {
optval = *mtod(m, int *);
switch (optname) {
case IP_TOS:
inp->inp_ip.ip_tos = optval;
break;
case IP_TTL:
inp->inp_ip.ip_ttl = optval;
break;
#define OPTSET(bit) \
if (optval) \
inp->inp_flags |= bit; \
else \
inp->inp_flags &= ~bit;
case IP_RECVOPTS:
OPTSET(INP_RECVOPTS);
break;
case IP_RECVRETOPTS:
OPTSET(INP_RECVRETOPTS);
break;
case IP_RECVDSTADDR:
OPTSET(INP_RECVDSTADDR);
break;
}
}
break;
#undef OPTSET
case IP_MULTICAST_IF:
case IP_MULTICAST_TTL:
case IP_MULTICAST_LOOP:
case IP_ADD_MEMBERSHIP:
case IP_DROP_MEMBERSHIP:
error = ip_setmoptions(optname, &inp->inp_moptions, m);
break;
default:
error = ENOPROTOOPT;
break;
}
if (m)
(void)m_free(m);
break;
case PRCO_GETOPT:
switch (optname) {
case IP_OPTIONS:
case IP_RETOPTS:
*mp = m = m_get(M_WAIT, MT_SOOPTS);
if (inp->inp_options) {
m->m_len = inp->inp_options->m_len;
bcopy(mtod(inp->inp_options, caddr_t),
mtod(m, caddr_t), (unsigned)m->m_len);
} else
m->m_len = 0;
break;
case IP_TOS:
case IP_TTL:
case IP_RECVOPTS:
case IP_RECVRETOPTS:
case IP_RECVDSTADDR:
*mp = m = m_get(M_WAIT, MT_SOOPTS);
m->m_len = sizeof(int);
switch (optname) {
case IP_TOS:
optval = inp->inp_ip.ip_tos;
break;
case IP_TTL:
optval = inp->inp_ip.ip_ttl;
break;
#define OPTBIT(bit) (inp->inp_flags & bit ? 1 : 0)
case IP_RECVOPTS:
optval = OPTBIT(INP_RECVOPTS);
break;
case IP_RECVRETOPTS:
optval = OPTBIT(INP_RECVRETOPTS);
break;
case IP_RECVDSTADDR:
optval = OPTBIT(INP_RECVDSTADDR);
break;
}
*mtod(m, int *) = optval;
break;
case IP_MULTICAST_IF:
case IP_MULTICAST_TTL:
case IP_MULTICAST_LOOP:
case IP_ADD_MEMBERSHIP:
case IP_DROP_MEMBERSHIP:
error = ip_getmoptions(optname, inp->inp_moptions, mp);
break;
default:
error = ENOPROTOOPT;
break;
}
break;
}
return (error);
}
/*
* Set up IP options in pcb for insertion in output packets.
* Store in mbuf with pointer in pcbopt, adding pseudo-option
* with destination address if source routed.
*/
int
#ifdef notyet
ip_pcbopts(optname, pcbopt, m)
int optname;
#else
ip_pcbopts(pcbopt, m)
#endif
struct mbuf **pcbopt;
register struct mbuf *m;
{
register cnt, optlen;
register u_char *cp;
u_char opt;
/* turn off any old options */
if (*pcbopt)
(void)m_free(*pcbopt);
*pcbopt = 0;
if (m == (struct mbuf *)0 || m->m_len == 0) {
/*
* Only turning off any previous options.
*/
if (m)
(void)m_free(m);
return (0);
}
#ifndef vax
if (m->m_len % sizeof(int32_t))
goto bad;
#endif
/*
* IP first-hop destination address will be stored before
* actual options; move other options back
* and clear it when none present.
*/
if (m->m_data + m->m_len + sizeof(struct in_addr) >= &m->m_dat[MLEN])
goto bad;
cnt = m->m_len;
m->m_len += sizeof(struct in_addr);
cp = mtod(m, u_char *) + sizeof(struct in_addr);
ovbcopy(mtod(m, caddr_t), (caddr_t)cp, (unsigned)cnt);
bzero(mtod(m, caddr_t), sizeof(struct in_addr));
for (; cnt > 0; cnt -= optlen, cp += optlen) {
opt = cp[IPOPT_OPTVAL];
if (opt == IPOPT_EOL)
break;
if (opt == IPOPT_NOP)
optlen = 1;
else {
optlen = cp[IPOPT_OLEN];
if (optlen <= IPOPT_OLEN || optlen > cnt)
goto bad;
}
switch (opt) {
default:
break;
case IPOPT_LSRR:
case IPOPT_SSRR:
/*
* user process specifies route as:
* ->A->B->C->D
* D must be our final destination (but we can't
* check that since we may not have connected yet).
* A is first hop destination, which doesn't appear in
* actual IP option, but is stored before the options.
*/
if (optlen < IPOPT_MINOFF - 1 + sizeof(struct in_addr))
goto bad;
m->m_len -= sizeof(struct in_addr);
cnt -= sizeof(struct in_addr);
optlen -= sizeof(struct in_addr);
cp[IPOPT_OLEN] = optlen;
/*
* Move first hop before start of options.
*/
bcopy((caddr_t)&cp[IPOPT_OFFSET+1], mtod(m, caddr_t),
sizeof(struct in_addr));
/*
* Then copy rest of options back
* to close up the deleted entry.
*/
ovbcopy((caddr_t)(&cp[IPOPT_OFFSET+1] +
sizeof(struct in_addr)),
(caddr_t)&cp[IPOPT_OFFSET+1],
(unsigned)cnt + sizeof(struct in_addr));
break;
}
}
if (m->m_len > MAX_IPOPTLEN + sizeof(struct in_addr))
goto bad;
*pcbopt = m;
return (0);
bad:
(void)m_free(m);
return (EINVAL);
}
/*
* Set the IP multicast options in response to user setsockopt().
*/
int
ip_setmoptions(optname, imop, m)
int optname;
struct ip_moptions **imop;
struct mbuf *m;
{
register int error = 0;
u_char loop;
register int i;
struct in_addr addr;
register struct ip_mreq *mreq;
register struct ifnet *ifp;
register struct ip_moptions *imo = *imop;
struct route ro;
register struct sockaddr_in *dst;
if (imo == NULL) {
/*
* No multicast option buffer attached to the pcb;
* allocate one and initialize to default values.
*/
imo = (struct ip_moptions *)malloc(sizeof(*imo), M_IPMOPTS,
M_WAITOK);
if (imo == NULL)
return (ENOBUFS);
*imop = imo;
imo->imo_multicast_ifp = NULL;
imo->imo_multicast_ttl = IP_DEFAULT_MULTICAST_TTL;
imo->imo_multicast_loop = IP_DEFAULT_MULTICAST_LOOP;
imo->imo_num_memberships = 0;
}
switch (optname) {
case IP_MULTICAST_IF:
/*
* Select the interface for outgoing multicast packets.
*/
if (m == NULL || m->m_len != sizeof(struct in_addr)) {
error = EINVAL;
break;
}
addr = *(mtod(m, struct in_addr *));
/*
* INADDR_ANY is used to remove a previous selection.
* When no interface is selected, a default one is
* chosen every time a multicast packet is sent.
*/
if (in_nullhost(addr)) {
imo->imo_multicast_ifp = NULL;
break;
}
/*
* The selected interface is identified by its local
* IP address. Find the interface and confirm that
* it supports multicasting.
*/
INADDR_TO_IFP(addr, ifp);
if (ifp == NULL || (ifp->if_flags & IFF_MULTICAST) == 0) {
error = EADDRNOTAVAIL;
break;
}
imo->imo_multicast_ifp = ifp;
break;
case IP_MULTICAST_TTL:
/*
* Set the IP time-to-live for outgoing multicast packets.
*/
if (m == NULL || m->m_len != 1) {
error = EINVAL;
break;
}
imo->imo_multicast_ttl = *(mtod(m, u_char *));
break;
case IP_MULTICAST_LOOP:
/*
* Set the loopback flag for outgoing multicast packets.
* Must be zero or one.
*/
if (m == NULL || m->m_len != 1 ||
(loop = *(mtod(m, u_char *))) > 1) {
error = EINVAL;
break;
}
imo->imo_multicast_loop = loop;
break;
case IP_ADD_MEMBERSHIP:
/*
* Add a multicast group membership.
* Group must be a valid IP multicast address.
*/
if (m == NULL || m->m_len != sizeof(struct ip_mreq)) {
error = EINVAL;
break;
}
mreq = mtod(m, struct ip_mreq *);
if (!IN_MULTICAST(mreq->imr_multiaddr.s_addr)) {
error = EINVAL;
break;
}
/*
* If no interface address was provided, use the interface of
* the route to the given multicast address.
*/
if (in_nullhost(mreq->imr_interface)) {
ro.ro_rt = NULL;
dst = satosin(&ro.ro_dst);
dst->sin_len = sizeof(*dst);
dst->sin_family = AF_INET;
dst->sin_addr = mreq->imr_multiaddr;
rtalloc(&ro);
if (ro.ro_rt == NULL) {
error = EADDRNOTAVAIL;
break;
}
ifp = ro.ro_rt->rt_ifp;
rtfree(ro.ro_rt);
} else {
INADDR_TO_IFP(mreq->imr_interface, ifp);
}
/*
* See if we found an interface, and confirm that it
* supports multicast.
*/
if (ifp == NULL || (ifp->if_flags & IFF_MULTICAST) == 0) {
error = EADDRNOTAVAIL;
break;
}
/*
* See if the membership already exists or if all the
* membership slots are full.
*/
for (i = 0; i < imo->imo_num_memberships; ++i) {
if (imo->imo_membership[i]->inm_ifp == ifp &&
in_hosteq(imo->imo_membership[i]->inm_addr,
mreq->imr_multiaddr))
break;
}
if (i < imo->imo_num_memberships) {
error = EADDRINUSE;
break;
}
if (i == IP_MAX_MEMBERSHIPS) {
error = ETOOMANYREFS;
break;
}
/*
* Everything looks good; add a new record to the multicast
* address list for the given interface.
*/
if ((imo->imo_membership[i] =
in_addmulti(&mreq->imr_multiaddr, ifp)) == NULL) {
error = ENOBUFS;
break;
}
++imo->imo_num_memberships;
break;
case IP_DROP_MEMBERSHIP:
/*
* Drop a multicast group membership.
* Group must be a valid IP multicast address.
*/
if (m == NULL || m->m_len != sizeof(struct ip_mreq)) {
error = EINVAL;
break;
}
mreq = mtod(m, struct ip_mreq *);
if (!IN_MULTICAST(mreq->imr_multiaddr.s_addr)) {
error = EINVAL;
break;
}
/*
* If an interface address was specified, get a pointer
* to its ifnet structure.
*/
if (in_nullhost(mreq->imr_interface))
ifp = NULL;
else {
INADDR_TO_IFP(mreq->imr_interface, ifp);
if (ifp == NULL) {
error = EADDRNOTAVAIL;
break;
}
}
/*
* Find the membership in the membership array.
*/
for (i = 0; i < imo->imo_num_memberships; ++i) {
if ((ifp == NULL ||
imo->imo_membership[i]->inm_ifp == ifp) &&
in_hosteq(imo->imo_membership[i]->inm_addr,
mreq->imr_multiaddr))
break;
}
if (i == imo->imo_num_memberships) {
error = EADDRNOTAVAIL;
break;
}
/*
* Give up the multicast address record to which the
* membership points.
*/
in_delmulti(imo->imo_membership[i]);
/*
* Remove the gap in the membership array.
*/
for (++i; i < imo->imo_num_memberships; ++i)
imo->imo_membership[i-1] = imo->imo_membership[i];
--imo->imo_num_memberships;
break;
default:
error = EOPNOTSUPP;
break;
}
/*
* If all options have default values, no need to keep the mbuf.
*/
if (imo->imo_multicast_ifp == NULL &&
imo->imo_multicast_ttl == IP_DEFAULT_MULTICAST_TTL &&
imo->imo_multicast_loop == IP_DEFAULT_MULTICAST_LOOP &&
imo->imo_num_memberships == 0) {
free(*imop, M_IPMOPTS);
*imop = NULL;
}
return (error);
}
/*
* Return the IP multicast options in response to user getsockopt().
*/
int
ip_getmoptions(optname, imo, mp)
int optname;
register struct ip_moptions *imo;
register struct mbuf **mp;
{
u_char *ttl;
u_char *loop;
struct in_addr *addr;
struct in_ifaddr *ia;
*mp = m_get(M_WAIT, MT_SOOPTS);
switch (optname) {
case IP_MULTICAST_IF:
addr = mtod(*mp, struct in_addr *);
(*mp)->m_len = sizeof(struct in_addr);
if (imo == NULL || imo->imo_multicast_ifp == NULL)
*addr = zeroin_addr;
else {
IFP_TO_IA(imo->imo_multicast_ifp, ia);
*addr = ia ? ia->ia_addr.sin_addr : zeroin_addr;
}
return (0);
case IP_MULTICAST_TTL:
ttl = mtod(*mp, u_char *);
(*mp)->m_len = 1;
*ttl = imo ? imo->imo_multicast_ttl
: IP_DEFAULT_MULTICAST_TTL;
return (0);
case IP_MULTICAST_LOOP:
loop = mtod(*mp, u_char *);
(*mp)->m_len = 1;
*loop = imo ? imo->imo_multicast_loop
: IP_DEFAULT_MULTICAST_LOOP;
return (0);
default:
return (EOPNOTSUPP);
}
}
/*
* Discard the IP multicast options.
*/
void
ip_freemoptions(imo)
register struct ip_moptions *imo;
{
register int i;
if (imo != NULL) {
for (i = 0; i < imo->imo_num_memberships; ++i)
in_delmulti(imo->imo_membership[i]);
free(imo, M_IPMOPTS);
}
}
/*
* Routine called from ip_output() to loop back a copy of an IP multicast
* packet to the input queue of a specified interface. Note that this
* calls the output routine of the loopback "driver", but with an interface
* pointer that might NOT be &loif -- easier than replicating that code here.
*/
static void
ip_mloopback(ifp, m, dst)
struct ifnet *ifp;
register struct mbuf *m;
register struct sockaddr_in *dst;
{
register struct ip *ip;
struct mbuf *copym;
copym = m_copy(m, 0, M_COPYALL);
if (copym != NULL) {
/*
* We don't bother to fragment if the IP length is greater
* than the interface's MTU. Can this possibly matter?
*/
ip = mtod(copym, struct ip *);
ip->ip_len = htons((u_int16_t)ip->ip_len);
ip->ip_off = htons((u_int16_t)ip->ip_off);
ip->ip_sum = 0;
ip->ip_sum = in_cksum(copym, ip->ip_hl << 2);
(void) looutput(ifp, copym, sintosa(dst), NULL);
}
}
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