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freebsd-nq/sys/netinet/udp_usrreq.c
Tom Rhodes 41698ebf5b Document a few sysctls. 
Reviewed by:	rwatson
2008-07-20 15:29:58 +00:00

1267 lines
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/*-
* Copyright (c) 1982, 1986, 1988, 1990, 1993, 1995
* The Regents of the University of California.
* Copyright (c) 2008 Robert N. M. Watson
* 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.
* 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.
*
* @(#)udp_usrreq.c 8.6 (Berkeley) 5/23/95
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_ipfw.h"
#include "opt_inet6.h"
#include "opt_ipsec.h"
#include "opt_mac.h"
#include <sys/param.h>
#include <sys/domain.h>
#include <sys/eventhandler.h>
#include <sys/jail.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/priv.h>
#include <sys/proc.h>
#include <sys/protosw.h>
#include <sys/signalvar.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/sx.h>
#include <sys/sysctl.h>
#include <sys/syslog.h>
#include <sys/systm.h>
#include <vm/uma.h>
#include <net/if.h>
#include <net/route.h>
#include <netinet/in.h>
#include <netinet/in_pcb.h>
#include <netinet/in_systm.h>
#include <netinet/in_var.h>
#include <netinet/ip.h>
#ifdef INET6
#include <netinet/ip6.h>
#endif
#include <netinet/ip_icmp.h>
#include <netinet/icmp_var.h>
#include <netinet/ip_var.h>
#include <netinet/ip_options.h>
#ifdef INET6
#include <netinet6/ip6_var.h>
#endif
#include <netinet/udp.h>
#include <netinet/udp_var.h>
#ifdef IPSEC
#include <netipsec/ipsec.h>
#endif
#include <machine/in_cksum.h>
#include <security/mac/mac_framework.h>
/*
* UDP protocol implementation.
* Per RFC 768, August, 1980.
*/
/*
* BSD 4.2 defaulted the udp checksum to be off. Turning off udp checksums
* removes the only data integrity mechanism for packets and malformed
* packets that would otherwise be discarded due to bad checksums, and may
* cause problems (especially for NFS data blocks).
*/
static int udp_cksum = 1;
SYSCTL_INT(_net_inet_udp, UDPCTL_CHECKSUM, checksum, CTLFLAG_RW, &udp_cksum,
0, "compute udp checksum");
int udp_log_in_vain = 0;
SYSCTL_INT(_net_inet_udp, OID_AUTO, log_in_vain, CTLFLAG_RW,
&udp_log_in_vain, 0, "Log all incoming UDP packets");
int udp_blackhole = 0;
SYSCTL_INT(_net_inet_udp, OID_AUTO, blackhole, CTLFLAG_RW, &udp_blackhole, 0,
"Do not send port unreachables for refused connects");
u_long udp_sendspace = 9216; /* really max datagram size */
/* 40 1K datagrams */
SYSCTL_ULONG(_net_inet_udp, UDPCTL_MAXDGRAM, maxdgram, CTLFLAG_RW,
&udp_sendspace, 0, "Maximum outgoing UDP datagram size");
u_long udp_recvspace = 40 * (1024 +
#ifdef INET6
sizeof(struct sockaddr_in6)
#else
sizeof(struct sockaddr_in)
#endif
);
SYSCTL_ULONG(_net_inet_udp, UDPCTL_RECVSPACE, recvspace, CTLFLAG_RW,
&udp_recvspace, 0, "Maximum space for incoming UDP datagrams");
struct inpcbhead udb; /* from udp_var.h */
struct inpcbinfo udbinfo;
#ifndef UDBHASHSIZE
#define UDBHASHSIZE 16
#endif
struct udpstat udpstat; /* from udp_var.h */
SYSCTL_STRUCT(_net_inet_udp, UDPCTL_STATS, stats, CTLFLAG_RW, &udpstat,
udpstat, "UDP statistics (struct udpstat, netinet/udp_var.h)");
static void udp_detach(struct socket *so);
static int udp_output(struct inpcb *, struct mbuf *, struct sockaddr *,
struct mbuf *, struct thread *);
static void
udp_zone_change(void *tag)
{
uma_zone_set_max(udbinfo.ipi_zone, maxsockets);
}
static int
udp_inpcb_init(void *mem, int size, int flags)
{
struct inpcb *inp;
inp = mem;
INP_LOCK_INIT(inp, "inp", "udpinp");
return (0);
}
void
udp_init(void)
{
INP_INFO_LOCK_INIT(&udbinfo, "udp");
LIST_INIT(&udb);
udbinfo.ipi_listhead = &udb;
udbinfo.ipi_hashbase = hashinit(UDBHASHSIZE, M_PCB,
&udbinfo.ipi_hashmask);
udbinfo.ipi_porthashbase = hashinit(UDBHASHSIZE, M_PCB,
&udbinfo.ipi_porthashmask);
udbinfo.ipi_zone = uma_zcreate("udpcb", sizeof(struct inpcb), NULL,
NULL, udp_inpcb_init, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE);
uma_zone_set_max(udbinfo.ipi_zone, maxsockets);
EVENTHANDLER_REGISTER(maxsockets_change, udp_zone_change, NULL,
EVENTHANDLER_PRI_ANY);
}
/*
* Subroutine of udp_input(), which appends the provided mbuf chain to the
* passed pcb/socket. The caller must provide a sockaddr_in via udp_in that
* contains the source address. If the socket ends up being an IPv6 socket,
* udp_append() will convert to a sockaddr_in6 before passing the address
* into the socket code.
*/
static void
udp_append(struct inpcb *inp, struct ip *ip, struct mbuf *n, int off,
struct sockaddr_in *udp_in)
{
struct sockaddr *append_sa;
struct socket *so;
struct mbuf *opts = 0;
#ifdef INET6
struct sockaddr_in6 udp_in6;
#endif
INP_RLOCK_ASSERT(inp);
#ifdef IPSEC
/* Check AH/ESP integrity. */
if (ipsec4_in_reject(n, inp)) {
m_freem(n);
ipsec4stat.in_polvio++;
return;
}
#endif /* IPSEC */
#ifdef MAC
if (mac_inpcb_check_deliver(inp, n) != 0) {
m_freem(n);
return;
}
#endif
if (inp->inp_flags & INP_CONTROLOPTS ||
inp->inp_socket->so_options & (SO_TIMESTAMP | SO_BINTIME)) {
#ifdef INET6
if (inp->inp_vflag & INP_IPV6)
ip6_savecontrol_v4(inp, n, &opts);
else
#endif
ip_savecontrol(inp, &opts, ip, n);
}
#ifdef INET6
if (inp->inp_vflag & INP_IPV6) {
bzero(&udp_in6, sizeof(udp_in6));
udp_in6.sin6_len = sizeof(udp_in6);
udp_in6.sin6_family = AF_INET6;
in6_sin_2_v4mapsin6(udp_in, &udp_in6);
append_sa = (struct sockaddr *)&udp_in6;
} else
#endif
append_sa = (struct sockaddr *)udp_in;
m_adj(n, off);
so = inp->inp_socket;
SOCKBUF_LOCK(&so->so_rcv);
if (sbappendaddr_locked(&so->so_rcv, append_sa, n, opts) == 0) {
SOCKBUF_UNLOCK(&so->so_rcv);
m_freem(n);
if (opts)
m_freem(opts);
udpstat.udps_fullsock++;
} else
sorwakeup_locked(so);
}
void
udp_input(struct mbuf *m, int off)
{
int iphlen = off;
struct ip *ip;
struct udphdr *uh;
struct ifnet *ifp;
struct inpcb *inp;
int len;
struct ip save_ip;
struct sockaddr_in udp_in;
#ifdef IPFIREWALL_FORWARD
struct m_tag *fwd_tag;
#endif
ifp = m->m_pkthdr.rcvif;
udpstat.udps_ipackets++;
/*
* Strip IP options, if any; should skip this, make available to
* user, and use on returned packets, but we don't yet have a way to
* check the checksum with options still present.
*/
if (iphlen > sizeof (struct ip)) {
ip_stripoptions(m, (struct mbuf *)0);
iphlen = sizeof(struct ip);
}
/*
* Get IP and UDP header together in first mbuf.
*/
ip = mtod(m, struct ip *);
if (m->m_len < iphlen + sizeof(struct udphdr)) {
if ((m = m_pullup(m, iphlen + sizeof(struct udphdr))) == 0) {
udpstat.udps_hdrops++;
return;
}
ip = mtod(m, struct ip *);
}
uh = (struct udphdr *)((caddr_t)ip + iphlen);
/*
* Destination port of 0 is illegal, based on RFC768.
*/
if (uh->uh_dport == 0)
goto badunlocked;
/*
* Construct sockaddr format source address. Stuff source address
* and datagram in user buffer.
*/
bzero(&udp_in, sizeof(udp_in));
udp_in.sin_len = sizeof(udp_in);
udp_in.sin_family = AF_INET;
udp_in.sin_port = uh->uh_sport;
udp_in.sin_addr = ip->ip_src;
/*
* Make mbuf data length reflect UDP length. If not enough data to
* reflect UDP length, drop.
*/
len = ntohs((u_short)uh->uh_ulen);
if (ip->ip_len != len) {
if (len > ip->ip_len || len < sizeof(struct udphdr)) {
udpstat.udps_badlen++;
goto badunlocked;
}
m_adj(m, len - ip->ip_len);
/* ip->ip_len = len; */
}
/*
* Save a copy of the IP header in case we want restore it for
* sending an ICMP error message in response.
*/
if (!udp_blackhole)
save_ip = *ip;
else
memset(&save_ip, 0, sizeof(save_ip));
/*
* Checksum extended UDP header and data.
*/
if (uh->uh_sum) {
u_short uh_sum;
if (m->m_pkthdr.csum_flags & CSUM_DATA_VALID) {
if (m->m_pkthdr.csum_flags & CSUM_PSEUDO_HDR)
uh_sum = m->m_pkthdr.csum_data;
else
uh_sum = in_pseudo(ip->ip_src.s_addr,
ip->ip_dst.s_addr, htonl((u_short)len +
m->m_pkthdr.csum_data + IPPROTO_UDP));
uh_sum ^= 0xffff;
} else {
char b[9];
bcopy(((struct ipovly *)ip)->ih_x1, b, 9);
bzero(((struct ipovly *)ip)->ih_x1, 9);
((struct ipovly *)ip)->ih_len = uh->uh_ulen;
uh_sum = in_cksum(m, len + sizeof (struct ip));
bcopy(b, ((struct ipovly *)ip)->ih_x1, 9);
}
if (uh_sum) {
udpstat.udps_badsum++;
m_freem(m);
return;
}
} else
udpstat.udps_nosum++;
#ifdef IPFIREWALL_FORWARD
/*
* Grab info from PACKET_TAG_IPFORWARD tag prepended to the chain.
*/
fwd_tag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL);
if (fwd_tag != NULL) {
struct sockaddr_in *next_hop;
/*
* Do the hack.
*/
next_hop = (struct sockaddr_in *)(fwd_tag + 1);
ip->ip_dst = next_hop->sin_addr;
uh->uh_dport = ntohs(next_hop->sin_port);
/*
* Remove the tag from the packet. We don't need it anymore.
*/
m_tag_delete(m, fwd_tag);
}
#endif
INP_INFO_RLOCK(&udbinfo);
if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr)) ||
in_broadcast(ip->ip_dst, ifp)) {
struct inpcb *last;
struct ip_moptions *imo;
last = NULL;
LIST_FOREACH(inp, &udb, inp_list) {
if (inp->inp_lport != uh->uh_dport)
continue;
#ifdef INET6
if ((inp->inp_vflag & INP_IPV4) == 0)
continue;
#endif
if (inp->inp_laddr.s_addr != INADDR_ANY &&
inp->inp_laddr.s_addr != ip->ip_dst.s_addr)
continue;
if (inp->inp_faddr.s_addr != INADDR_ANY &&
inp->inp_faddr.s_addr != ip->ip_src.s_addr)
continue;
/*
* XXX: Do not check source port of incoming datagram
* unless inp_connect() has been called to bind the
* fport part of the 4-tuple; the source could be
* trying to talk to us with an ephemeral port.
*/
if (inp->inp_fport != 0 &&
inp->inp_fport != uh->uh_sport)
continue;
INP_RLOCK(inp);
/*
* Handle socket delivery policy for any-source
* and source-specific multicast. [RFC3678]
*/
imo = inp->inp_moptions;
if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr)) &&
imo != NULL) {
struct sockaddr_in sin;
struct in_msource *ims;
int blocked, mode;
size_t idx;
bzero(&sin, sizeof(struct sockaddr_in));
sin.sin_len = sizeof(struct sockaddr_in);
sin.sin_family = AF_INET;
sin.sin_addr = ip->ip_dst;
blocked = 0;
idx = imo_match_group(imo, ifp,
(struct sockaddr *)&sin);
if (idx == -1) {
/*
* No group membership for this socket.
* Do not bump udps_noportbcast, as
* this will happen further down.
*/
blocked++;
} else {
/*
* Check for a multicast source filter
* entry on this socket for this group.
* MCAST_EXCLUDE is the default
* behaviour. It means default accept;
* entries, if present, denote sources
* to be excluded from delivery.
*/
ims = imo_match_source(imo, idx,
(struct sockaddr *)&udp_in);
mode = imo->imo_mfilters[idx].imf_fmode;
if ((ims != NULL &&
mode == MCAST_EXCLUDE) ||
(ims == NULL &&
mode == MCAST_INCLUDE)) {
#ifdef DIAGNOSTIC
if (bootverbose) {
printf("%s: blocked by"
" source filter\n",
__func__);
}
#endif
udpstat.udps_filtermcast++;
blocked++;
}
}
if (blocked != 0) {
INP_RUNLOCK(inp);
continue;
}
}
if (last != NULL) {
struct mbuf *n;
n = m_copy(m, 0, M_COPYALL);
if (n != NULL)
udp_append(last, ip, n, iphlen +
sizeof(struct udphdr), &udp_in);
INP_RUNLOCK(last);
}
last = inp;
/*
* Don't look for additional matches if this one does
* not have either the SO_REUSEPORT or SO_REUSEADDR
* socket options set. This heuristic avoids
* searching through all pcbs in the common case of a
* non-shared port. It assumes that an application
* will never clear these options after setting them.
*/
if ((last->inp_socket->so_options &
(SO_REUSEPORT|SO_REUSEADDR)) == 0)
break;
}
if (last == NULL) {
/*
* No matching pcb found; discard datagram. (No need
* to send an ICMP Port Unreachable for a broadcast
* or multicast datgram.)
*/
udpstat.udps_noportbcast++;
goto badheadlocked;
}
udp_append(last, ip, m, iphlen + sizeof(struct udphdr),
&udp_in);
INP_RUNLOCK(last);
INP_INFO_RUNLOCK(&udbinfo);
return;
}
/*
* Locate pcb for datagram.
*/
inp = in_pcblookup_hash(&udbinfo, ip->ip_src, uh->uh_sport,
ip->ip_dst, uh->uh_dport, 1, ifp);
if (inp == NULL) {
if (udp_log_in_vain) {
char buf[4*sizeof "123"];
strcpy(buf, inet_ntoa(ip->ip_dst));
log(LOG_INFO,
"Connection attempt to UDP %s:%d from %s:%d\n",
buf, ntohs(uh->uh_dport), inet_ntoa(ip->ip_src),
ntohs(uh->uh_sport));
}
udpstat.udps_noport++;
if (m->m_flags & (M_BCAST | M_MCAST)) {
udpstat.udps_noportbcast++;
goto badheadlocked;
}
if (udp_blackhole)
goto badheadlocked;
if (badport_bandlim(BANDLIM_ICMP_UNREACH) < 0)
goto badheadlocked;
*ip = save_ip;
ip->ip_len += iphlen;
icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_PORT, 0, 0);
INP_INFO_RUNLOCK(&udbinfo);
return;
}
/*
* Check the minimum TTL for socket.
*/
INP_RLOCK(inp);
INP_INFO_RUNLOCK(&udbinfo);
if (inp->inp_ip_minttl && inp->inp_ip_minttl > ip->ip_ttl) {
INP_RUNLOCK(inp);
goto badunlocked;
}
udp_append(inp, ip, m, iphlen + sizeof(struct udphdr), &udp_in);
INP_RUNLOCK(inp);
return;
badheadlocked:
if (inp)
INP_RUNLOCK(inp);
INP_INFO_RUNLOCK(&udbinfo);
badunlocked:
m_freem(m);
}
/*
* Notify a udp user of an asynchronous error; just wake up so that they can
* collect error status.
*/
struct inpcb *
udp_notify(struct inpcb *inp, int errno)
{
/*
* While udp_ctlinput() always calls udp_notify() with a read lock
* when invoking it directly, in_pcbnotifyall() currently uses write
* locks due to sharing code with TCP. For now, accept either a read
* or a write lock, but a read lock is sufficient.
*/
INP_LOCK_ASSERT(inp);
inp->inp_socket->so_error = errno;
sorwakeup(inp->inp_socket);
sowwakeup(inp->inp_socket);
return (inp);
}
void
udp_ctlinput(int cmd, struct sockaddr *sa, void *vip)
{
struct ip *ip = vip;
struct udphdr *uh;
struct in_addr faddr;
struct inpcb *inp;
faddr = ((struct sockaddr_in *)sa)->sin_addr;
if (sa->sa_family != AF_INET || faddr.s_addr == INADDR_ANY)
return;
/*
* Redirects don't need to be handled up here.
*/
if (PRC_IS_REDIRECT(cmd))
return;
/*
* Hostdead is ugly because it goes linearly through all PCBs.
*
* XXX: We never get this from ICMP, otherwise it makes an excellent
* DoS attack on machines with many connections.
*/
if (cmd == PRC_HOSTDEAD)
ip = NULL;
else if ((unsigned)cmd >= PRC_NCMDS || inetctlerrmap[cmd] == 0)
return;
if (ip != NULL) {
uh = (struct udphdr *)((caddr_t)ip + (ip->ip_hl << 2));
INP_INFO_RLOCK(&udbinfo);
inp = in_pcblookup_hash(&udbinfo, faddr, uh->uh_dport,
ip->ip_src, uh->uh_sport, 0, NULL);
if (inp != NULL) {
INP_RLOCK(inp);
if (inp->inp_socket != NULL) {
udp_notify(inp, inetctlerrmap[cmd]);
}
INP_RUNLOCK(inp);
}
INP_INFO_RUNLOCK(&udbinfo);
} else
in_pcbnotifyall(&udbinfo, faddr, inetctlerrmap[cmd],
udp_notify);
}
static int
udp_pcblist(SYSCTL_HANDLER_ARGS)
{
int error, i, n;
struct inpcb *inp, **inp_list;
inp_gen_t gencnt;
struct xinpgen xig;
/*
* The process of preparing the PCB list is too time-consuming and
* resource-intensive to repeat twice on every request.
*/
if (req->oldptr == 0) {
n = udbinfo.ipi_count;
req->oldidx = 2 * (sizeof xig)
+ (n + n/8) * sizeof(struct xinpcb);
return (0);
}
if (req->newptr != 0)
return (EPERM);
/*
* OK, now we're committed to doing something.
*/
INP_INFO_RLOCK(&udbinfo);
gencnt = udbinfo.ipi_gencnt;
n = udbinfo.ipi_count;
INP_INFO_RUNLOCK(&udbinfo);
error = sysctl_wire_old_buffer(req, 2 * (sizeof xig)
+ n * sizeof(struct xinpcb));
if (error != 0)
return (error);
xig.xig_len = sizeof xig;
xig.xig_count = n;
xig.xig_gen = gencnt;
xig.xig_sogen = so_gencnt;
error = SYSCTL_OUT(req, &xig, sizeof xig);
if (error)
return (error);
inp_list = malloc(n * sizeof *inp_list, M_TEMP, M_WAITOK);
if (inp_list == 0)
return (ENOMEM);
INP_INFO_RLOCK(&udbinfo);
for (inp = LIST_FIRST(udbinfo.ipi_listhead), i = 0; inp && i < n;
inp = LIST_NEXT(inp, inp_list)) {
INP_RLOCK(inp);
if (inp->inp_gencnt <= gencnt &&
cr_canseesocket(req->td->td_ucred, inp->inp_socket) == 0)
inp_list[i++] = inp;
INP_RUNLOCK(inp);
}
INP_INFO_RUNLOCK(&udbinfo);
n = i;
error = 0;
for (i = 0; i < n; i++) {
inp = inp_list[i];
INP_RLOCK(inp);
if (inp->inp_gencnt <= gencnt) {
struct xinpcb xi;
bzero(&xi, sizeof(xi));
xi.xi_len = sizeof xi;
/* XXX should avoid extra copy */
bcopy(inp, &xi.xi_inp, sizeof *inp);
if (inp->inp_socket)
sotoxsocket(inp->inp_socket, &xi.xi_socket);
xi.xi_inp.inp_gencnt = inp->inp_gencnt;
INP_RUNLOCK(inp);
error = SYSCTL_OUT(req, &xi, sizeof xi);
} else
INP_RUNLOCK(inp);
}
if (!error) {
/*
* Give the user an updated idea of our state. If the
* generation differs from what we told her before, she knows
* that something happened while we were processing this
* request, and it might be necessary to retry.
*/
INP_INFO_RLOCK(&udbinfo);
xig.xig_gen = udbinfo.ipi_gencnt;
xig.xig_sogen = so_gencnt;
xig.xig_count = udbinfo.ipi_count;
INP_INFO_RUNLOCK(&udbinfo);
error = SYSCTL_OUT(req, &xig, sizeof xig);
}
free(inp_list, M_TEMP);
return (error);
}
SYSCTL_PROC(_net_inet_udp, UDPCTL_PCBLIST, pcblist, CTLFLAG_RD, 0, 0,
udp_pcblist, "S,xinpcb", "List of active UDP sockets");
static int
udp_getcred(SYSCTL_HANDLER_ARGS)
{
struct xucred xuc;
struct sockaddr_in addrs[2];
struct inpcb *inp;
int error;
error = priv_check(req->td, PRIV_NETINET_GETCRED);
if (error)
return (error);
error = SYSCTL_IN(req, addrs, sizeof(addrs));
if (error)
return (error);
INP_INFO_RLOCK(&udbinfo);
inp = in_pcblookup_hash(&udbinfo, addrs[1].sin_addr, addrs[1].sin_port,
addrs[0].sin_addr, addrs[0].sin_port, 1, NULL);
if (inp != NULL) {
INP_RLOCK(inp);
INP_INFO_RUNLOCK(&udbinfo);
if (inp->inp_socket == NULL)
error = ENOENT;
if (error == 0)
error = cr_canseesocket(req->td->td_ucred,
inp->inp_socket);
if (error == 0)
cru2x(inp->inp_socket->so_cred, &xuc);
INP_RUNLOCK(inp);
} else {
INP_INFO_RUNLOCK(&udbinfo);
error = ENOENT;
}
if (error == 0)
error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred));
return (error);
}
SYSCTL_PROC(_net_inet_udp, OID_AUTO, getcred,
CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_PRISON, 0, 0,
udp_getcred, "S,xucred", "Get the xucred of a UDP connection");
static int
udp_output(struct inpcb *inp, struct mbuf *m, struct sockaddr *addr,
struct mbuf *control, struct thread *td)
{
struct udpiphdr *ui;
int len = m->m_pkthdr.len;
struct in_addr faddr, laddr;
struct cmsghdr *cm;
struct sockaddr_in *sin, src;
int error = 0;
int ipflags;
u_short fport, lport;
int unlock_udbinfo;
/*
* udp_output() may need to temporarily bind or connect the current
* inpcb. As such, we don't know up front whether we will need the
* pcbinfo lock or not. Do any work to decide what is needed up
* front before acquiring any locks.
*/
if (len + sizeof(struct udpiphdr) > IP_MAXPACKET) {
if (control)
m_freem(control);
m_freem(m);
return (EMSGSIZE);
}
src.sin_family = 0;
if (control != NULL) {
/*
* XXX: Currently, we assume all the optional information is
* stored in a single mbuf.
*/
if (control->m_next) {
m_freem(control);
m_freem(m);
return (EINVAL);
}
for (; control->m_len > 0;
control->m_data += CMSG_ALIGN(cm->cmsg_len),
control->m_len -= CMSG_ALIGN(cm->cmsg_len)) {
cm = mtod(control, struct cmsghdr *);
if (control->m_len < sizeof(*cm) || cm->cmsg_len == 0
|| cm->cmsg_len > control->m_len) {
error = EINVAL;
break;
}
if (cm->cmsg_level != IPPROTO_IP)
continue;
switch (cm->cmsg_type) {
case IP_SENDSRCADDR:
if (cm->cmsg_len !=
CMSG_LEN(sizeof(struct in_addr))) {
error = EINVAL;
break;
}
bzero(&src, sizeof(src));
src.sin_family = AF_INET;
src.sin_len = sizeof(src);
src.sin_port = inp->inp_lport;
src.sin_addr =
*(struct in_addr *)CMSG_DATA(cm);
break;
default:
error = ENOPROTOOPT;
break;
}
if (error)
break;
}
m_freem(control);
}
if (error) {
m_freem(m);
return (error);
}
/*
* Depending on whether or not the application has bound or connected
* the socket, we may have to do varying levels of work. The optimal
* case is for a connected UDP socket, as a global lock isn't
* required at all.
*
* In order to decide which we need, we require stability of the
* inpcb binding, which we ensure by acquiring a read lock on the
* inpcb. This doesn't strictly follow the lock order, so we play
* the trylock and retry game; note that we may end up with more
* conservative locks than required the second time around, so later
* assertions have to accept that. Further analysis of the number of
* misses under contention is required.
*/
sin = (struct sockaddr_in *)addr;
INP_RLOCK(inp);
if (sin != NULL &&
(inp->inp_laddr.s_addr == INADDR_ANY && inp->inp_lport == 0)) {
INP_RUNLOCK(inp);
INP_INFO_WLOCK(&udbinfo);
INP_WLOCK(inp);
unlock_udbinfo = 2;
} else if ((sin != NULL && (
(sin->sin_addr.s_addr == INADDR_ANY) ||
(sin->sin_addr.s_addr == INADDR_BROADCAST) ||
(inp->inp_laddr.s_addr == INADDR_ANY) ||
(inp->inp_lport == 0))) ||
(src.sin_family == AF_INET)) {
if (!INP_INFO_TRY_RLOCK(&udbinfo)) {
INP_RUNLOCK(inp);
INP_INFO_RLOCK(&udbinfo);
INP_RLOCK(inp);
}
unlock_udbinfo = 1;
} else
unlock_udbinfo = 0;
/*
* If the IP_SENDSRCADDR control message was specified, override the
* source address for this datagram. Its use is invalidated if the
* address thus specified is incomplete or clobbers other inpcbs.
*/
laddr = inp->inp_laddr;
lport = inp->inp_lport;
if (src.sin_family == AF_INET) {
INP_INFO_LOCK_ASSERT(&udbinfo);
if ((lport == 0) ||
(laddr.s_addr == INADDR_ANY &&
src.sin_addr.s_addr == INADDR_ANY)) {
error = EINVAL;
goto release;
}
error = in_pcbbind_setup(inp, (struct sockaddr *)&src,
&laddr.s_addr, &lport, td->td_ucred);
if (error)
goto release;
}
/*
* If a UDP socket has been connected, then a local address/port will
* have been selected and bound.
*
* If a UDP socket has not been connected to, then an explicit
* destination address must be used, in which case a local
* address/port may not have been selected and bound.
*/
if (sin != NULL) {
INP_LOCK_ASSERT(inp);
if (inp->inp_faddr.s_addr != INADDR_ANY) {
error = EISCONN;
goto release;
}
/*
* Jail may rewrite the destination address, so let it do
* that before we use it.
*/
if (jailed(td->td_ucred))
prison_remote_ip(td->td_ucred, 0,
&sin->sin_addr.s_addr);
/*
* If a local address or port hasn't yet been selected, or if
* the destination address needs to be rewritten due to using
* a special INADDR_ constant, invoke in_pcbconnect_setup()
* to do the heavy lifting. Once a port is selected, we
* commit the binding back to the socket; we also commit the
* binding of the address if in jail.
*
* If we already have a valid binding and we're not
* requesting a destination address rewrite, use a fast path.
*/
if (inp->inp_laddr.s_addr == INADDR_ANY ||
inp->inp_lport == 0 ||
sin->sin_addr.s_addr == INADDR_ANY ||
sin->sin_addr.s_addr == INADDR_BROADCAST) {
INP_INFO_LOCK_ASSERT(&udbinfo);
error = in_pcbconnect_setup(inp, addr, &laddr.s_addr,
&lport, &faddr.s_addr, &fport, NULL,
td->td_ucred);
if (error)
goto release;
/*
* XXXRW: Why not commit the port if the address is
* !INADDR_ANY?
*/
/* Commit the local port if newly assigned. */
if (inp->inp_laddr.s_addr == INADDR_ANY &&
inp->inp_lport == 0) {
INP_INFO_WLOCK_ASSERT(&udbinfo);
INP_WLOCK_ASSERT(inp);
/*
* Remember addr if jailed, to prevent
* rebinding.
*/
if (jailed(td->td_ucred))
inp->inp_laddr = laddr;
inp->inp_lport = lport;
if (in_pcbinshash(inp) != 0) {
inp->inp_lport = 0;
error = EAGAIN;
goto release;
}
inp->inp_flags |= INP_ANONPORT;
}
} else {
faddr = sin->sin_addr;
fport = sin->sin_port;
}
} else {
INP_LOCK_ASSERT(inp);
faddr = inp->inp_faddr;
fport = inp->inp_fport;
if (faddr.s_addr == INADDR_ANY) {
error = ENOTCONN;
goto release;
}
}
/*
* Calculate data length and get a mbuf for UDP, IP, and possible
* link-layer headers. Immediate slide the data pointer back forward
* since we won't use that space at this layer.
*/
M_PREPEND(m, sizeof(struct udpiphdr) + max_linkhdr, M_DONTWAIT);
if (m == NULL) {
error = ENOBUFS;
goto release;
}
m->m_data += max_linkhdr;
m->m_len -= max_linkhdr;
m->m_pkthdr.len -= max_linkhdr;
/*
* Fill in mbuf with extended UDP header and addresses and length put
* into network format.
*/
ui = mtod(m, struct udpiphdr *);
bzero(ui->ui_x1, sizeof(ui->ui_x1)); /* XXX still needed? */
ui->ui_pr = IPPROTO_UDP;
ui->ui_src = laddr;
ui->ui_dst = faddr;
ui->ui_sport = lport;
ui->ui_dport = fport;
ui->ui_ulen = htons((u_short)len + sizeof(struct udphdr));
/*
* Set the Don't Fragment bit in the IP header.
*/
if (inp->inp_flags & INP_DONTFRAG) {
struct ip *ip;
ip = (struct ip *)&ui->ui_i;
ip->ip_off |= IP_DF;
}
ipflags = 0;
if (inp->inp_socket->so_options & SO_DONTROUTE)
ipflags |= IP_ROUTETOIF;
if (inp->inp_socket->so_options & SO_BROADCAST)
ipflags |= IP_ALLOWBROADCAST;
if (inp->inp_flags & INP_ONESBCAST)
ipflags |= IP_SENDONES;
#ifdef MAC
mac_inpcb_create_mbuf(inp, m);
#endif
/*
* Set up checksum and output datagram.
*/
if (udp_cksum) {
if (inp->inp_flags & INP_ONESBCAST)
faddr.s_addr = INADDR_BROADCAST;
ui->ui_sum = in_pseudo(ui->ui_src.s_addr, faddr.s_addr,
htons((u_short)len + sizeof(struct udphdr) + IPPROTO_UDP));
m->m_pkthdr.csum_flags = CSUM_UDP;
m->m_pkthdr.csum_data = offsetof(struct udphdr, uh_sum);
} else
ui->ui_sum = 0;
((struct ip *)ui)->ip_len = sizeof (struct udpiphdr) + len;
((struct ip *)ui)->ip_ttl = inp->inp_ip_ttl; /* XXX */
((struct ip *)ui)->ip_tos = inp->inp_ip_tos; /* XXX */
udpstat.udps_opackets++;
if (unlock_udbinfo == 2)
INP_INFO_WUNLOCK(&udbinfo);
else if (unlock_udbinfo == 1)
INP_INFO_RUNLOCK(&udbinfo);
error = ip_output(m, inp->inp_options, NULL, ipflags,
inp->inp_moptions, inp);
if (unlock_udbinfo == 2)
INP_WUNLOCK(inp);
else
INP_RUNLOCK(inp);
return (error);
release:
if (unlock_udbinfo == 2) {
INP_WUNLOCK(inp);
INP_INFO_WUNLOCK(&udbinfo);
} else if (unlock_udbinfo == 1) {
INP_RUNLOCK(inp);
INP_INFO_RUNLOCK(&udbinfo);
} else
INP_RUNLOCK(inp);
m_freem(m);
return (error);
}
static void
udp_abort(struct socket *so)
{
struct inpcb *inp;
inp = sotoinpcb(so);
KASSERT(inp != NULL, ("udp_abort: inp == NULL"));
INP_INFO_WLOCK(&udbinfo);
INP_WLOCK(inp);
if (inp->inp_faddr.s_addr != INADDR_ANY) {
in_pcbdisconnect(inp);
inp->inp_laddr.s_addr = INADDR_ANY;
soisdisconnected(so);
}
INP_WUNLOCK(inp);
INP_INFO_WUNLOCK(&udbinfo);
}
static int
udp_attach(struct socket *so, int proto, struct thread *td)
{
struct inpcb *inp;
int error;
inp = sotoinpcb(so);
KASSERT(inp == NULL, ("udp_attach: inp != NULL"));
error = soreserve(so, udp_sendspace, udp_recvspace);
if (error)
return (error);
INP_INFO_WLOCK(&udbinfo);
error = in_pcballoc(so, &udbinfo);
if (error) {
INP_INFO_WUNLOCK(&udbinfo);
return (error);
}
inp = (struct inpcb *)so->so_pcb;
INP_INFO_WUNLOCK(&udbinfo);
inp->inp_vflag |= INP_IPV4;
inp->inp_ip_ttl = ip_defttl;
INP_WUNLOCK(inp);
return (0);
}
static int
udp_bind(struct socket *so, struct sockaddr *nam, struct thread *td)
{
struct inpcb *inp;
int error;
inp = sotoinpcb(so);
KASSERT(inp != NULL, ("udp_bind: inp == NULL"));
INP_INFO_WLOCK(&udbinfo);
INP_WLOCK(inp);
error = in_pcbbind(inp, nam, td->td_ucred);
INP_WUNLOCK(inp);
INP_INFO_WUNLOCK(&udbinfo);
return (error);
}
static void
udp_close(struct socket *so)
{
struct inpcb *inp;
inp = sotoinpcb(so);
KASSERT(inp != NULL, ("udp_close: inp == NULL"));
INP_INFO_WLOCK(&udbinfo);
INP_WLOCK(inp);
if (inp->inp_faddr.s_addr != INADDR_ANY) {
in_pcbdisconnect(inp);
inp->inp_laddr.s_addr = INADDR_ANY;
soisdisconnected(so);
}
INP_WUNLOCK(inp);
INP_INFO_WUNLOCK(&udbinfo);
}
static int
udp_connect(struct socket *so, struct sockaddr *nam, struct thread *td)
{
struct inpcb *inp;
int error;
struct sockaddr_in *sin;
inp = sotoinpcb(so);
KASSERT(inp != NULL, ("udp_connect: inp == NULL"));
INP_INFO_WLOCK(&udbinfo);
INP_WLOCK(inp);
if (inp->inp_faddr.s_addr != INADDR_ANY) {
INP_WUNLOCK(inp);
INP_INFO_WUNLOCK(&udbinfo);
return (EISCONN);
}
sin = (struct sockaddr_in *)nam;
if (jailed(td->td_ucred))
prison_remote_ip(td->td_ucred, 0, &sin->sin_addr.s_addr);
error = in_pcbconnect(inp, nam, td->td_ucred);
if (error == 0)
soisconnected(so);
INP_WUNLOCK(inp);
INP_INFO_WUNLOCK(&udbinfo);
return (error);
}
static void
udp_detach(struct socket *so)
{
struct inpcb *inp;
inp = sotoinpcb(so);
KASSERT(inp != NULL, ("udp_detach: inp == NULL"));
KASSERT(inp->inp_faddr.s_addr == INADDR_ANY,
("udp_detach: not disconnected"));
INP_INFO_WLOCK(&udbinfo);
INP_WLOCK(inp);
in_pcbdetach(inp);
in_pcbfree(inp);
INP_INFO_WUNLOCK(&udbinfo);
}
static int
udp_disconnect(struct socket *so)
{
struct inpcb *inp;
inp = sotoinpcb(so);
KASSERT(inp != NULL, ("udp_disconnect: inp == NULL"));
INP_INFO_WLOCK(&udbinfo);
INP_WLOCK(inp);
if (inp->inp_faddr.s_addr == INADDR_ANY) {
INP_WUNLOCK(inp);
INP_INFO_WUNLOCK(&udbinfo);
return (ENOTCONN);
}
in_pcbdisconnect(inp);
inp->inp_laddr.s_addr = INADDR_ANY;
SOCK_LOCK(so);
so->so_state &= ~SS_ISCONNECTED; /* XXX */
SOCK_UNLOCK(so);
INP_WUNLOCK(inp);
INP_INFO_WUNLOCK(&udbinfo);
return (0);
}
static int
udp_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *addr,
struct mbuf *control, struct thread *td)
{
struct inpcb *inp;
inp = sotoinpcb(so);
KASSERT(inp != NULL, ("udp_send: inp == NULL"));
return (udp_output(inp, m, addr, control, td));
}
int
udp_shutdown(struct socket *so)
{
struct inpcb *inp;
inp = sotoinpcb(so);
KASSERT(inp != NULL, ("udp_shutdown: inp == NULL"));
INP_WLOCK(inp);
socantsendmore(so);
INP_WUNLOCK(inp);
return (0);
}
struct pr_usrreqs udp_usrreqs = {
.pru_abort = udp_abort,
.pru_attach = udp_attach,
.pru_bind = udp_bind,
.pru_connect = udp_connect,
.pru_control = in_control,
.pru_detach = udp_detach,
.pru_disconnect = udp_disconnect,
.pru_peeraddr = in_getpeeraddr,
.pru_send = udp_send,
.pru_soreceive = soreceive_dgram,
.pru_sosend = sosend_dgram,
.pru_shutdown = udp_shutdown,
.pru_sockaddr = in_getsockaddr,
.pru_sosetlabel = in_pcbsosetlabel,
.pru_close = udp_close,
};
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