The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/netinet/udp_usrreq.c

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    1 /*-
    2  * Copyright (c) 1982, 1986, 1988, 1990, 1993, 1995
    3  *      The Regents of the University of California.
    4  * Copyright (c) 2008 Robert N. M. Watson
    5  * Copyright (c) 2010-2011 Juniper Networks, Inc.
    6  * All rights reserved.
    7  *
    8  * Portions of this software were developed by Robert N. M. Watson under
    9  * contract to Juniper Networks, Inc.
   10  *
   11  * Redistribution and use in source and binary forms, with or without
   12  * modification, are permitted provided that the following conditions
   13  * are met:
   14  * 1. Redistributions of source code must retain the above copyright
   15  *    notice, this list of conditions and the following disclaimer.
   16  * 2. Redistributions in binary form must reproduce the above copyright
   17  *    notice, this list of conditions and the following disclaimer in the
   18  *    documentation and/or other materials provided with the distribution.
   19  * 4. Neither the name of the University nor the names of its contributors
   20  *    may be used to endorse or promote products derived from this software
   21  *    without specific prior written permission.
   22  *
   23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   33  * SUCH DAMAGE.
   34  *
   35  *      @(#)udp_usrreq.c        8.6 (Berkeley) 5/23/95
   36  */
   37 
   38 #include <sys/cdefs.h>
   39 __FBSDID("$FreeBSD: releng/9.2/sys/netinet/udp_usrreq.c 252692 2013-07-04 08:57:13Z ae $");
   40 
   41 #include "opt_ipfw.h"
   42 #include "opt_inet.h"
   43 #include "opt_inet6.h"
   44 #include "opt_ipsec.h"
   45 
   46 #include <sys/param.h>
   47 #include <sys/domain.h>
   48 #include <sys/eventhandler.h>
   49 #include <sys/jail.h>
   50 #include <sys/kernel.h>
   51 #include <sys/lock.h>
   52 #include <sys/malloc.h>
   53 #include <sys/mbuf.h>
   54 #include <sys/priv.h>
   55 #include <sys/proc.h>
   56 #include <sys/protosw.h>
   57 #include <sys/signalvar.h>
   58 #include <sys/socket.h>
   59 #include <sys/socketvar.h>
   60 #include <sys/sx.h>
   61 #include <sys/sysctl.h>
   62 #include <sys/syslog.h>
   63 #include <sys/systm.h>
   64 
   65 #include <vm/uma.h>
   66 
   67 #include <net/if.h>
   68 #include <net/route.h>
   69 
   70 #include <netinet/in.h>
   71 #include <netinet/in_pcb.h>
   72 #include <netinet/in_systm.h>
   73 #include <netinet/in_var.h>
   74 #include <netinet/ip.h>
   75 #ifdef INET6
   76 #include <netinet/ip6.h>
   77 #endif
   78 #include <netinet/ip_icmp.h>
   79 #include <netinet/icmp_var.h>
   80 #include <netinet/ip_var.h>
   81 #include <netinet/ip_options.h>
   82 #ifdef INET6
   83 #include <netinet6/ip6_var.h>
   84 #endif
   85 #include <netinet/udp.h>
   86 #include <netinet/udp_var.h>
   87 
   88 #ifdef IPSEC
   89 #include <netipsec/ipsec.h>
   90 #include <netipsec/esp.h>
   91 #endif
   92 
   93 #include <machine/in_cksum.h>
   94 
   95 #include <security/mac/mac_framework.h>
   96 
   97 /*
   98  * UDP protocol implementation.
   99  * Per RFC 768, August, 1980.
  100  */
  101 
  102 /*
  103  * BSD 4.2 defaulted the udp checksum to be off.  Turning off udp checksums
  104  * removes the only data integrity mechanism for packets and malformed
  105  * packets that would otherwise be discarded due to bad checksums, and may
  106  * cause problems (especially for NFS data blocks).
  107  */
  108 VNET_DEFINE(int, udp_cksum) = 1;
  109 SYSCTL_VNET_INT(_net_inet_udp, UDPCTL_CHECKSUM, checksum, CTLFLAG_RW,
  110     &VNET_NAME(udp_cksum), 0, "compute udp checksum");
  111 
  112 int     udp_log_in_vain = 0;
  113 SYSCTL_INT(_net_inet_udp, OID_AUTO, log_in_vain, CTLFLAG_RW,
  114     &udp_log_in_vain, 0, "Log all incoming UDP packets");
  115 
  116 VNET_DEFINE(int, udp_blackhole) = 0;
  117 SYSCTL_VNET_INT(_net_inet_udp, OID_AUTO, blackhole, CTLFLAG_RW,
  118     &VNET_NAME(udp_blackhole), 0,
  119     "Do not send port unreachables for refused connects");
  120 
  121 u_long  udp_sendspace = 9216;           /* really max datagram size */
  122                                         /* 40 1K datagrams */
  123 SYSCTL_ULONG(_net_inet_udp, UDPCTL_MAXDGRAM, maxdgram, CTLFLAG_RW,
  124     &udp_sendspace, 0, "Maximum outgoing UDP datagram size");
  125 
  126 u_long  udp_recvspace = 40 * (1024 +
  127 #ifdef INET6
  128                                       sizeof(struct sockaddr_in6)
  129 #else
  130                                       sizeof(struct sockaddr_in)
  131 #endif
  132                                       );
  133 
  134 SYSCTL_ULONG(_net_inet_udp, UDPCTL_RECVSPACE, recvspace, CTLFLAG_RW,
  135     &udp_recvspace, 0, "Maximum space for incoming UDP datagrams");
  136 
  137 VNET_DEFINE(struct inpcbhead, udb);             /* from udp_var.h */
  138 VNET_DEFINE(struct inpcbinfo, udbinfo);
  139 static VNET_DEFINE(uma_zone_t, udpcb_zone);
  140 #define V_udpcb_zone                    VNET(udpcb_zone)
  141 
  142 #ifndef UDBHASHSIZE
  143 #define UDBHASHSIZE     128
  144 #endif
  145 
  146 VNET_DEFINE(struct udpstat, udpstat);           /* from udp_var.h */
  147 SYSCTL_VNET_STRUCT(_net_inet_udp, UDPCTL_STATS, stats, CTLFLAG_RW,
  148     &VNET_NAME(udpstat), udpstat,
  149     "UDP statistics (struct udpstat, netinet/udp_var.h)");
  150 
  151 #ifdef INET
  152 static void     udp_detach(struct socket *so);
  153 static int      udp_output(struct inpcb *, struct mbuf *, struct sockaddr *,
  154                     struct mbuf *, struct thread *);
  155 #endif
  156 
  157 #ifdef IPSEC
  158 #ifdef IPSEC_NAT_T
  159 #define UF_ESPINUDP_ALL (UF_ESPINUDP_NON_IKE|UF_ESPINUDP)
  160 #ifdef INET
  161 static struct mbuf *udp4_espdecap(struct inpcb *, struct mbuf *, int);
  162 #endif
  163 #endif /* IPSEC_NAT_T */
  164 #endif /* IPSEC */
  165 
  166 static void
  167 udp_zone_change(void *tag)
  168 {
  169 
  170         uma_zone_set_max(V_udbinfo.ipi_zone, maxsockets);
  171         uma_zone_set_max(V_udpcb_zone, maxsockets);
  172 }
  173 
  174 static int
  175 udp_inpcb_init(void *mem, int size, int flags)
  176 {
  177         struct inpcb *inp;
  178 
  179         inp = mem;
  180         INP_LOCK_INIT(inp, "inp", "udpinp");
  181         return (0);
  182 }
  183 
  184 void
  185 udp_init(void)
  186 {
  187 
  188         in_pcbinfo_init(&V_udbinfo, "udp", &V_udb, UDBHASHSIZE, UDBHASHSIZE,
  189             "udp_inpcb", udp_inpcb_init, NULL, UMA_ZONE_NOFREE,
  190             IPI_HASHFIELDS_2TUPLE);
  191         V_udpcb_zone = uma_zcreate("udpcb", sizeof(struct udpcb),
  192             NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE);
  193         uma_zone_set_max(V_udpcb_zone, maxsockets);
  194         EVENTHANDLER_REGISTER(maxsockets_change, udp_zone_change, NULL,
  195             EVENTHANDLER_PRI_ANY);
  196 }
  197 
  198 /*
  199  * Kernel module interface for updating udpstat.  The argument is an index
  200  * into udpstat treated as an array of u_long.  While this encodes the
  201  * general layout of udpstat into the caller, it doesn't encode its location,
  202  * so that future changes to add, for example, per-CPU stats support won't
  203  * cause binary compatibility problems for kernel modules.
  204  */
  205 void
  206 kmod_udpstat_inc(int statnum)
  207 {
  208 
  209         (*((u_long *)&V_udpstat + statnum))++;
  210 }
  211 
  212 int
  213 udp_newudpcb(struct inpcb *inp)
  214 {
  215         struct udpcb *up;
  216 
  217         up = uma_zalloc(V_udpcb_zone, M_NOWAIT | M_ZERO);
  218         if (up == NULL)
  219                 return (ENOBUFS);
  220         inp->inp_ppcb = up;
  221         return (0);
  222 }
  223 
  224 void
  225 udp_discardcb(struct udpcb *up)
  226 {
  227 
  228         uma_zfree(V_udpcb_zone, up);
  229 }
  230 
  231 #ifdef VIMAGE
  232 void
  233 udp_destroy(void)
  234 {
  235 
  236         in_pcbinfo_destroy(&V_udbinfo);
  237         uma_zdestroy(V_udpcb_zone);
  238 }
  239 #endif
  240 
  241 #ifdef INET
  242 /*
  243  * Subroutine of udp_input(), which appends the provided mbuf chain to the
  244  * passed pcb/socket.  The caller must provide a sockaddr_in via udp_in that
  245  * contains the source address.  If the socket ends up being an IPv6 socket,
  246  * udp_append() will convert to a sockaddr_in6 before passing the address
  247  * into the socket code.
  248  */
  249 static void
  250 udp_append(struct inpcb *inp, struct ip *ip, struct mbuf *n, int off,
  251     struct sockaddr_in *udp_in)
  252 {
  253         struct sockaddr *append_sa;
  254         struct socket *so;
  255         struct mbuf *opts = 0;
  256 #ifdef INET6
  257         struct sockaddr_in6 udp_in6;
  258 #endif
  259         struct udpcb *up;
  260 
  261         INP_LOCK_ASSERT(inp);
  262 
  263         /*
  264          * Engage the tunneling protocol.
  265          */
  266         up = intoudpcb(inp);
  267         if (up->u_tun_func != NULL) {
  268                 (*up->u_tun_func)(n, off, inp);
  269                 return;
  270         }
  271 
  272         if (n == NULL)
  273                 return;
  274 
  275         off += sizeof(struct udphdr);
  276 
  277 #ifdef IPSEC
  278         /* Check AH/ESP integrity. */
  279         if (ipsec4_in_reject(n, inp)) {
  280                 m_freem(n);
  281                 IPSECSTAT_INC(in_polvio);
  282                 return;
  283         }
  284 #ifdef IPSEC_NAT_T
  285         up = intoudpcb(inp);
  286         KASSERT(up != NULL, ("%s: udpcb NULL", __func__));
  287         if (up->u_flags & UF_ESPINUDP_ALL) {    /* IPSec UDP encaps. */
  288                 n = udp4_espdecap(inp, n, off);
  289                 if (n == NULL)                          /* Consumed. */
  290                         return;
  291         }
  292 #endif /* IPSEC_NAT_T */
  293 #endif /* IPSEC */
  294 #ifdef MAC
  295         if (mac_inpcb_check_deliver(inp, n) != 0) {
  296                 m_freem(n);
  297                 return;
  298         }
  299 #endif /* MAC */
  300         if (inp->inp_flags & INP_CONTROLOPTS ||
  301             inp->inp_socket->so_options & (SO_TIMESTAMP | SO_BINTIME)) {
  302 #ifdef INET6
  303                 if (inp->inp_vflag & INP_IPV6)
  304                         (void)ip6_savecontrol_v4(inp, n, &opts, NULL);
  305                 else
  306 #endif /* INET6 */
  307                         ip_savecontrol(inp, &opts, ip, n);
  308         }
  309 #ifdef INET6
  310         if (inp->inp_vflag & INP_IPV6) {
  311                 bzero(&udp_in6, sizeof(udp_in6));
  312                 udp_in6.sin6_len = sizeof(udp_in6);
  313                 udp_in6.sin6_family = AF_INET6;
  314                 in6_sin_2_v4mapsin6(udp_in, &udp_in6);
  315                 append_sa = (struct sockaddr *)&udp_in6;
  316         } else
  317 #endif /* INET6 */
  318                 append_sa = (struct sockaddr *)udp_in;
  319         m_adj(n, off);
  320 
  321         so = inp->inp_socket;
  322         SOCKBUF_LOCK(&so->so_rcv);
  323         if (sbappendaddr_locked(&so->so_rcv, append_sa, n, opts) == 0) {
  324                 SOCKBUF_UNLOCK(&so->so_rcv);
  325                 m_freem(n);
  326                 if (opts)
  327                         m_freem(opts);
  328                 UDPSTAT_INC(udps_fullsock);
  329         } else
  330                 sorwakeup_locked(so);
  331 }
  332 
  333 void
  334 udp_input(struct mbuf *m, int off)
  335 {
  336         int iphlen = off;
  337         struct ip *ip;
  338         struct udphdr *uh;
  339         struct ifnet *ifp;
  340         struct inpcb *inp;
  341         int len;
  342         struct ip save_ip;
  343         struct sockaddr_in udp_in;
  344         struct m_tag *fwd_tag;
  345 
  346         ifp = m->m_pkthdr.rcvif;
  347         UDPSTAT_INC(udps_ipackets);
  348 
  349         /*
  350          * Strip IP options, if any; should skip this, make available to
  351          * user, and use on returned packets, but we don't yet have a way to
  352          * check the checksum with options still present.
  353          */
  354         if (iphlen > sizeof (struct ip)) {
  355                 ip_stripoptions(m, (struct mbuf *)0);
  356                 iphlen = sizeof(struct ip);
  357         }
  358 
  359         /*
  360          * Get IP and UDP header together in first mbuf.
  361          */
  362         ip = mtod(m, struct ip *);
  363         if (m->m_len < iphlen + sizeof(struct udphdr)) {
  364                 if ((m = m_pullup(m, iphlen + sizeof(struct udphdr))) == 0) {
  365                         UDPSTAT_INC(udps_hdrops);
  366                         return;
  367                 }
  368                 ip = mtod(m, struct ip *);
  369         }
  370         uh = (struct udphdr *)((caddr_t)ip + iphlen);
  371 
  372         /*
  373          * Destination port of 0 is illegal, based on RFC768.
  374          */
  375         if (uh->uh_dport == 0)
  376                 goto badunlocked;
  377 
  378         /*
  379          * Construct sockaddr format source address.  Stuff source address
  380          * and datagram in user buffer.
  381          */
  382         bzero(&udp_in, sizeof(udp_in));
  383         udp_in.sin_len = sizeof(udp_in);
  384         udp_in.sin_family = AF_INET;
  385         udp_in.sin_port = uh->uh_sport;
  386         udp_in.sin_addr = ip->ip_src;
  387 
  388         /*
  389          * Make mbuf data length reflect UDP length.  If not enough data to
  390          * reflect UDP length, drop.
  391          */
  392         len = ntohs((u_short)uh->uh_ulen);
  393         if (ip->ip_len != len) {
  394                 if (len > ip->ip_len || len < sizeof(struct udphdr)) {
  395                         UDPSTAT_INC(udps_badlen);
  396                         goto badunlocked;
  397                 }
  398                 m_adj(m, len - ip->ip_len);
  399                 /* ip->ip_len = len; */
  400         }
  401 
  402         /*
  403          * Save a copy of the IP header in case we want restore it for
  404          * sending an ICMP error message in response.
  405          */
  406         if (!V_udp_blackhole)
  407                 save_ip = *ip;
  408         else
  409                 memset(&save_ip, 0, sizeof(save_ip));
  410 
  411         /*
  412          * Checksum extended UDP header and data.
  413          */
  414         if (uh->uh_sum) {
  415                 u_short uh_sum;
  416 
  417                 if (m->m_pkthdr.csum_flags & CSUM_DATA_VALID) {
  418                         if (m->m_pkthdr.csum_flags & CSUM_PSEUDO_HDR)
  419                                 uh_sum = m->m_pkthdr.csum_data;
  420                         else
  421                                 uh_sum = in_pseudo(ip->ip_src.s_addr,
  422                                     ip->ip_dst.s_addr, htonl((u_short)len +
  423                                     m->m_pkthdr.csum_data + IPPROTO_UDP));
  424                         uh_sum ^= 0xffff;
  425                 } else {
  426                         char b[9];
  427 
  428                         bcopy(((struct ipovly *)ip)->ih_x1, b, 9);
  429                         bzero(((struct ipovly *)ip)->ih_x1, 9);
  430                         ((struct ipovly *)ip)->ih_len = uh->uh_ulen;
  431                         uh_sum = in_cksum(m, len + sizeof (struct ip));
  432                         bcopy(b, ((struct ipovly *)ip)->ih_x1, 9);
  433                 }
  434                 if (uh_sum) {
  435                         UDPSTAT_INC(udps_badsum);
  436                         m_freem(m);
  437                         return;
  438                 }
  439         } else
  440                 UDPSTAT_INC(udps_nosum);
  441 
  442         if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr)) ||
  443             in_broadcast(ip->ip_dst, ifp)) {
  444                 struct inpcb *last;
  445                 struct ip_moptions *imo;
  446 
  447                 INP_INFO_RLOCK(&V_udbinfo);
  448                 last = NULL;
  449                 LIST_FOREACH(inp, &V_udb, inp_list) {
  450                         if (inp->inp_lport != uh->uh_dport)
  451                                 continue;
  452 #ifdef INET6
  453                         if ((inp->inp_vflag & INP_IPV4) == 0)
  454                                 continue;
  455 #endif
  456                         if (inp->inp_laddr.s_addr != INADDR_ANY &&
  457                             inp->inp_laddr.s_addr != ip->ip_dst.s_addr)
  458                                 continue;
  459                         if (inp->inp_faddr.s_addr != INADDR_ANY &&
  460                             inp->inp_faddr.s_addr != ip->ip_src.s_addr)
  461                                 continue;
  462                         if (inp->inp_fport != 0 &&
  463                             inp->inp_fport != uh->uh_sport)
  464                                 continue;
  465 
  466                         INP_RLOCK(inp);
  467 
  468                         /*
  469                          * XXXRW: Because we weren't holding either the inpcb
  470                          * or the hash lock when we checked for a match
  471                          * before, we should probably recheck now that the
  472                          * inpcb lock is held.
  473                          */
  474 
  475                         /*
  476                          * Handle socket delivery policy for any-source
  477                          * and source-specific multicast. [RFC3678]
  478                          */
  479                         imo = inp->inp_moptions;
  480                         if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) {
  481                                 struct sockaddr_in       group;
  482                                 int                      blocked;
  483                                 if (imo == NULL) {
  484                                         INP_RUNLOCK(inp);
  485                                         continue;
  486                                 }
  487                                 bzero(&group, sizeof(struct sockaddr_in));
  488                                 group.sin_len = sizeof(struct sockaddr_in);
  489                                 group.sin_family = AF_INET;
  490                                 group.sin_addr = ip->ip_dst;
  491 
  492                                 blocked = imo_multi_filter(imo, ifp,
  493                                         (struct sockaddr *)&group,
  494                                         (struct sockaddr *)&udp_in);
  495                                 if (blocked != MCAST_PASS) {
  496                                         if (blocked == MCAST_NOTGMEMBER)
  497                                                 IPSTAT_INC(ips_notmember);
  498                                         if (blocked == MCAST_NOTSMEMBER ||
  499                                             blocked == MCAST_MUTED)
  500                                                 UDPSTAT_INC(udps_filtermcast);
  501                                         INP_RUNLOCK(inp);
  502                                         continue;
  503                                 }
  504                         }
  505                         if (last != NULL) {
  506                                 struct mbuf *n;
  507 
  508                                 n = m_copy(m, 0, M_COPYALL);
  509                                 udp_append(last, ip, n, iphlen, &udp_in);
  510                                 INP_RUNLOCK(last);
  511                         }
  512                         last = inp;
  513                         /*
  514                          * Don't look for additional matches if this one does
  515                          * not have either the SO_REUSEPORT or SO_REUSEADDR
  516                          * socket options set.  This heuristic avoids
  517                          * searching through all pcbs in the common case of a
  518                          * non-shared port.  It assumes that an application
  519                          * will never clear these options after setting them.
  520                          */
  521                         if ((last->inp_socket->so_options &
  522                             (SO_REUSEPORT|SO_REUSEADDR)) == 0)
  523                                 break;
  524                 }
  525 
  526                 if (last == NULL) {
  527                         /*
  528                          * No matching pcb found; discard datagram.  (No need
  529                          * to send an ICMP Port Unreachable for a broadcast
  530                          * or multicast datgram.)
  531                          */
  532                         UDPSTAT_INC(udps_noportbcast);
  533                         if (inp)
  534                                 INP_RUNLOCK(inp);
  535                         INP_INFO_RUNLOCK(&V_udbinfo);
  536                         goto badunlocked;
  537                 }
  538                 udp_append(last, ip, m, iphlen, &udp_in);
  539                 INP_RUNLOCK(last);
  540                 INP_INFO_RUNLOCK(&V_udbinfo);
  541                 return;
  542         }
  543 
  544         /*
  545          * Locate pcb for datagram.
  546          */
  547 
  548         /*
  549          * Grab info from PACKET_TAG_IPFORWARD tag prepended to the chain.
  550          */
  551         if ((m->m_flags & M_IP_NEXTHOP) &&
  552             (fwd_tag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL)) != NULL) {
  553                 struct sockaddr_in *next_hop;
  554 
  555                 next_hop = (struct sockaddr_in *)(fwd_tag + 1);
  556 
  557                 /*
  558                  * Transparently forwarded. Pretend to be the destination.
  559                  * Already got one like this?
  560                  */
  561                 inp = in_pcblookup_mbuf(&V_udbinfo, ip->ip_src, uh->uh_sport,
  562                     ip->ip_dst, uh->uh_dport, INPLOOKUP_RLOCKPCB, ifp, m);
  563                 if (!inp) {
  564                         /*
  565                          * It's new.  Try to find the ambushing socket.
  566                          * Because we've rewritten the destination address,
  567                          * any hardware-generated hash is ignored.
  568                          */
  569                         inp = in_pcblookup(&V_udbinfo, ip->ip_src,
  570                             uh->uh_sport, next_hop->sin_addr,
  571                             next_hop->sin_port ? htons(next_hop->sin_port) :
  572                             uh->uh_dport, INPLOOKUP_WILDCARD |
  573                             INPLOOKUP_RLOCKPCB, ifp);
  574                 }
  575                 /* Remove the tag from the packet. We don't need it anymore. */
  576                 m_tag_delete(m, fwd_tag);
  577                 m->m_flags &= ~M_IP_NEXTHOP;
  578         } else
  579                 inp = in_pcblookup_mbuf(&V_udbinfo, ip->ip_src, uh->uh_sport,
  580                     ip->ip_dst, uh->uh_dport, INPLOOKUP_WILDCARD |
  581                     INPLOOKUP_RLOCKPCB, ifp, m);
  582         if (inp == NULL) {
  583                 if (udp_log_in_vain) {
  584                         char buf[4*sizeof "123"];
  585 
  586                         strcpy(buf, inet_ntoa(ip->ip_dst));
  587                         log(LOG_INFO,
  588                             "Connection attempt to UDP %s:%d from %s:%d\n",
  589                             buf, ntohs(uh->uh_dport), inet_ntoa(ip->ip_src),
  590                             ntohs(uh->uh_sport));
  591                 }
  592                 UDPSTAT_INC(udps_noport);
  593                 if (m->m_flags & (M_BCAST | M_MCAST)) {
  594                         UDPSTAT_INC(udps_noportbcast);
  595                         goto badunlocked;
  596                 }
  597                 if (V_udp_blackhole)
  598                         goto badunlocked;
  599                 if (badport_bandlim(BANDLIM_ICMP_UNREACH) < 0)
  600                         goto badunlocked;
  601                 *ip = save_ip;
  602                 ip->ip_len += iphlen;
  603                 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_PORT, 0, 0);
  604                 return;
  605         }
  606 
  607         /*
  608          * Check the minimum TTL for socket.
  609          */
  610         INP_RLOCK_ASSERT(inp);
  611         if (inp->inp_ip_minttl && inp->inp_ip_minttl > ip->ip_ttl) {
  612                 INP_RUNLOCK(inp);
  613                 m_freem(m);
  614                 return;
  615         }
  616         udp_append(inp, ip, m, iphlen, &udp_in);
  617         INP_RUNLOCK(inp);
  618         return;
  619 
  620 badunlocked:
  621         m_freem(m);
  622 }
  623 #endif /* INET */
  624 
  625 /*
  626  * Notify a udp user of an asynchronous error; just wake up so that they can
  627  * collect error status.
  628  */
  629 struct inpcb *
  630 udp_notify(struct inpcb *inp, int errno)
  631 {
  632 
  633         /*
  634          * While udp_ctlinput() always calls udp_notify() with a read lock
  635          * when invoking it directly, in_pcbnotifyall() currently uses write
  636          * locks due to sharing code with TCP.  For now, accept either a read
  637          * or a write lock, but a read lock is sufficient.
  638          */
  639         INP_LOCK_ASSERT(inp);
  640 
  641         inp->inp_socket->so_error = errno;
  642         sorwakeup(inp->inp_socket);
  643         sowwakeup(inp->inp_socket);
  644         return (inp);
  645 }
  646 
  647 #ifdef INET
  648 void
  649 udp_ctlinput(int cmd, struct sockaddr *sa, void *vip)
  650 {
  651         struct ip *ip = vip;
  652         struct udphdr *uh;
  653         struct in_addr faddr;
  654         struct inpcb *inp;
  655 
  656         faddr = ((struct sockaddr_in *)sa)->sin_addr;
  657         if (sa->sa_family != AF_INET || faddr.s_addr == INADDR_ANY)
  658                 return;
  659 
  660         /*
  661          * Redirects don't need to be handled up here.
  662          */
  663         if (PRC_IS_REDIRECT(cmd))
  664                 return;
  665 
  666         /*
  667          * Hostdead is ugly because it goes linearly through all PCBs.
  668          *
  669          * XXX: We never get this from ICMP, otherwise it makes an excellent
  670          * DoS attack on machines with many connections.
  671          */
  672         if (cmd == PRC_HOSTDEAD)
  673                 ip = NULL;
  674         else if ((unsigned)cmd >= PRC_NCMDS || inetctlerrmap[cmd] == 0)
  675                 return;
  676         if (ip != NULL) {
  677                 uh = (struct udphdr *)((caddr_t)ip + (ip->ip_hl << 2));
  678                 inp = in_pcblookup(&V_udbinfo, faddr, uh->uh_dport,
  679                     ip->ip_src, uh->uh_sport, INPLOOKUP_RLOCKPCB, NULL);
  680                 if (inp != NULL) {
  681                         INP_RLOCK_ASSERT(inp);
  682                         if (inp->inp_socket != NULL) {
  683                                 udp_notify(inp, inetctlerrmap[cmd]);
  684                         }
  685                         INP_RUNLOCK(inp);
  686                 }
  687         } else
  688                 in_pcbnotifyall(&V_udbinfo, faddr, inetctlerrmap[cmd],
  689                     udp_notify);
  690 }
  691 #endif /* INET */
  692 
  693 static int
  694 udp_pcblist(SYSCTL_HANDLER_ARGS)
  695 {
  696         int error, i, n;
  697         struct inpcb *inp, **inp_list;
  698         inp_gen_t gencnt;
  699         struct xinpgen xig;
  700 
  701         /*
  702          * The process of preparing the PCB list is too time-consuming and
  703          * resource-intensive to repeat twice on every request.
  704          */
  705         if (req->oldptr == 0) {
  706                 n = V_udbinfo.ipi_count;
  707                 n += imax(n / 8, 10);
  708                 req->oldidx = 2 * (sizeof xig) + n * sizeof(struct xinpcb);
  709                 return (0);
  710         }
  711 
  712         if (req->newptr != 0)
  713                 return (EPERM);
  714 
  715         /*
  716          * OK, now we're committed to doing something.
  717          */
  718         INP_INFO_RLOCK(&V_udbinfo);
  719         gencnt = V_udbinfo.ipi_gencnt;
  720         n = V_udbinfo.ipi_count;
  721         INP_INFO_RUNLOCK(&V_udbinfo);
  722 
  723         error = sysctl_wire_old_buffer(req, 2 * (sizeof xig)
  724                 + n * sizeof(struct xinpcb));
  725         if (error != 0)
  726                 return (error);
  727 
  728         xig.xig_len = sizeof xig;
  729         xig.xig_count = n;
  730         xig.xig_gen = gencnt;
  731         xig.xig_sogen = so_gencnt;
  732         error = SYSCTL_OUT(req, &xig, sizeof xig);
  733         if (error)
  734                 return (error);
  735 
  736         inp_list = malloc(n * sizeof *inp_list, M_TEMP, M_WAITOK);
  737         if (inp_list == 0)
  738                 return (ENOMEM);
  739 
  740         INP_INFO_RLOCK(&V_udbinfo);
  741         for (inp = LIST_FIRST(V_udbinfo.ipi_listhead), i = 0; inp && i < n;
  742              inp = LIST_NEXT(inp, inp_list)) {
  743                 INP_WLOCK(inp);
  744                 if (inp->inp_gencnt <= gencnt &&
  745                     cr_canseeinpcb(req->td->td_ucred, inp) == 0) {
  746                         in_pcbref(inp);
  747                         inp_list[i++] = inp;
  748                 }
  749                 INP_WUNLOCK(inp);
  750         }
  751         INP_INFO_RUNLOCK(&V_udbinfo);
  752         n = i;
  753 
  754         error = 0;
  755         for (i = 0; i < n; i++) {
  756                 inp = inp_list[i];
  757                 INP_RLOCK(inp);
  758                 if (inp->inp_gencnt <= gencnt) {
  759                         struct xinpcb xi;
  760 
  761                         bzero(&xi, sizeof(xi));
  762                         xi.xi_len = sizeof xi;
  763                         /* XXX should avoid extra copy */
  764                         bcopy(inp, &xi.xi_inp, sizeof *inp);
  765                         if (inp->inp_socket)
  766                                 sotoxsocket(inp->inp_socket, &xi.xi_socket);
  767                         xi.xi_inp.inp_gencnt = inp->inp_gencnt;
  768                         INP_RUNLOCK(inp);
  769                         error = SYSCTL_OUT(req, &xi, sizeof xi);
  770                 } else
  771                         INP_RUNLOCK(inp);
  772         }
  773         INP_INFO_WLOCK(&V_udbinfo);
  774         for (i = 0; i < n; i++) {
  775                 inp = inp_list[i];
  776                 INP_RLOCK(inp);
  777                 if (!in_pcbrele_rlocked(inp))
  778                         INP_RUNLOCK(inp);
  779         }
  780         INP_INFO_WUNLOCK(&V_udbinfo);
  781 
  782         if (!error) {
  783                 /*
  784                  * Give the user an updated idea of our state.  If the
  785                  * generation differs from what we told her before, she knows
  786                  * that something happened while we were processing this
  787                  * request, and it might be necessary to retry.
  788                  */
  789                 INP_INFO_RLOCK(&V_udbinfo);
  790                 xig.xig_gen = V_udbinfo.ipi_gencnt;
  791                 xig.xig_sogen = so_gencnt;
  792                 xig.xig_count = V_udbinfo.ipi_count;
  793                 INP_INFO_RUNLOCK(&V_udbinfo);
  794                 error = SYSCTL_OUT(req, &xig, sizeof xig);
  795         }
  796         free(inp_list, M_TEMP);
  797         return (error);
  798 }
  799 
  800 SYSCTL_PROC(_net_inet_udp, UDPCTL_PCBLIST, pcblist,
  801     CTLTYPE_OPAQUE | CTLFLAG_RD, NULL, 0,
  802     udp_pcblist, "S,xinpcb", "List of active UDP sockets");
  803 
  804 #ifdef INET
  805 static int
  806 udp_getcred(SYSCTL_HANDLER_ARGS)
  807 {
  808         struct xucred xuc;
  809         struct sockaddr_in addrs[2];
  810         struct inpcb *inp;
  811         int error;
  812 
  813         error = priv_check(req->td, PRIV_NETINET_GETCRED);
  814         if (error)
  815                 return (error);
  816         error = SYSCTL_IN(req, addrs, sizeof(addrs));
  817         if (error)
  818                 return (error);
  819         inp = in_pcblookup(&V_udbinfo, addrs[1].sin_addr, addrs[1].sin_port,
  820             addrs[0].sin_addr, addrs[0].sin_port,
  821             INPLOOKUP_WILDCARD | INPLOOKUP_RLOCKPCB, NULL);
  822         if (inp != NULL) {
  823                 INP_RLOCK_ASSERT(inp);
  824                 if (inp->inp_socket == NULL)
  825                         error = ENOENT;
  826                 if (error == 0)
  827                         error = cr_canseeinpcb(req->td->td_ucred, inp);
  828                 if (error == 0)
  829                         cru2x(inp->inp_cred, &xuc);
  830                 INP_RUNLOCK(inp);
  831         } else
  832                 error = ENOENT;
  833         if (error == 0)
  834                 error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred));
  835         return (error);
  836 }
  837 
  838 SYSCTL_PROC(_net_inet_udp, OID_AUTO, getcred,
  839     CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_PRISON, 0, 0,
  840     udp_getcred, "S,xucred", "Get the xucred of a UDP connection");
  841 #endif /* INET */
  842 
  843 int
  844 udp_ctloutput(struct socket *so, struct sockopt *sopt)
  845 {
  846         int error = 0, optval;
  847         struct inpcb *inp;
  848 #ifdef IPSEC_NAT_T
  849         struct udpcb *up;
  850 #endif
  851 
  852         inp = sotoinpcb(so);
  853         KASSERT(inp != NULL, ("%s: inp == NULL", __func__));
  854         INP_WLOCK(inp);
  855         if (sopt->sopt_level != IPPROTO_UDP) {
  856 #ifdef INET6
  857                 if (INP_CHECK_SOCKAF(so, AF_INET6)) {
  858                         INP_WUNLOCK(inp);
  859                         error = ip6_ctloutput(so, sopt);
  860                 }
  861 #endif
  862 #if defined(INET) && defined(INET6)
  863                 else
  864 #endif
  865 #ifdef INET
  866                 {
  867                         INP_WUNLOCK(inp);
  868                         error = ip_ctloutput(so, sopt);
  869                 }
  870 #endif
  871                 return (error);
  872         }
  873 
  874         switch (sopt->sopt_dir) {
  875         case SOPT_SET:
  876                 switch (sopt->sopt_name) {
  877                 case UDP_ENCAP:
  878                         INP_WUNLOCK(inp);
  879                         error = sooptcopyin(sopt, &optval, sizeof optval,
  880                                             sizeof optval);
  881                         if (error)
  882                                 break;
  883                         inp = sotoinpcb(so);
  884                         KASSERT(inp != NULL, ("%s: inp == NULL", __func__));
  885                         INP_WLOCK(inp);
  886 #ifdef IPSEC_NAT_T
  887                         up = intoudpcb(inp);
  888                         KASSERT(up != NULL, ("%s: up == NULL", __func__));
  889 #endif
  890                         switch (optval) {
  891                         case 0:
  892                                 /* Clear all UDP encap. */
  893 #ifdef IPSEC_NAT_T
  894                                 up->u_flags &= ~UF_ESPINUDP_ALL;
  895 #endif
  896                                 break;
  897 #ifdef IPSEC_NAT_T
  898                         case UDP_ENCAP_ESPINUDP:
  899                         case UDP_ENCAP_ESPINUDP_NON_IKE:
  900                                 up->u_flags &= ~UF_ESPINUDP_ALL;
  901                                 if (optval == UDP_ENCAP_ESPINUDP)
  902                                         up->u_flags |= UF_ESPINUDP;
  903                                 else if (optval == UDP_ENCAP_ESPINUDP_NON_IKE)
  904                                         up->u_flags |= UF_ESPINUDP_NON_IKE;
  905                                 break;
  906 #endif
  907                         default:
  908                                 error = EINVAL;
  909                                 break;
  910                         }
  911                         INP_WUNLOCK(inp);
  912                         break;
  913                 default:
  914                         INP_WUNLOCK(inp);
  915                         error = ENOPROTOOPT;
  916                         break;
  917                 }
  918                 break;
  919         case SOPT_GET:
  920                 switch (sopt->sopt_name) {
  921 #ifdef IPSEC_NAT_T
  922                 case UDP_ENCAP:
  923                         up = intoudpcb(inp);
  924                         KASSERT(up != NULL, ("%s: up == NULL", __func__));
  925                         optval = up->u_flags & UF_ESPINUDP_ALL;
  926                         INP_WUNLOCK(inp);
  927                         error = sooptcopyout(sopt, &optval, sizeof optval);
  928                         break;
  929 #endif
  930                 default:
  931                         INP_WUNLOCK(inp);
  932                         error = ENOPROTOOPT;
  933                         break;
  934                 }
  935                 break;
  936         }       
  937         return (error);
  938 }
  939 
  940 #ifdef INET
  941 #define UH_WLOCKED      2
  942 #define UH_RLOCKED      1
  943 #define UH_UNLOCKED     0
  944 static int
  945 udp_output(struct inpcb *inp, struct mbuf *m, struct sockaddr *addr,
  946     struct mbuf *control, struct thread *td)
  947 {
  948         struct udpiphdr *ui;
  949         int len = m->m_pkthdr.len;
  950         struct in_addr faddr, laddr;
  951         struct cmsghdr *cm;
  952         struct sockaddr_in *sin, src;
  953         int error = 0;
  954         int ipflags;
  955         u_short fport, lport;
  956         int unlock_udbinfo;
  957         u_char tos;
  958 
  959         /*
  960          * udp_output() may need to temporarily bind or connect the current
  961          * inpcb.  As such, we don't know up front whether we will need the
  962          * pcbinfo lock or not.  Do any work to decide what is needed up
  963          * front before acquiring any locks.
  964          */
  965         if (len + sizeof(struct udpiphdr) > IP_MAXPACKET) {
  966                 if (control)
  967                         m_freem(control);
  968                 m_freem(m);
  969                 return (EMSGSIZE);
  970         }
  971 
  972         src.sin_family = 0;
  973         INP_RLOCK(inp);
  974         tos = inp->inp_ip_tos;
  975         if (control != NULL) {
  976                 /*
  977                  * XXX: Currently, we assume all the optional information is
  978                  * stored in a single mbuf.
  979                  */
  980                 if (control->m_next) {
  981                         INP_RUNLOCK(inp);
  982                         m_freem(control);
  983                         m_freem(m);
  984                         return (EINVAL);
  985                 }
  986                 for (; control->m_len > 0;
  987                     control->m_data += CMSG_ALIGN(cm->cmsg_len),
  988                     control->m_len -= CMSG_ALIGN(cm->cmsg_len)) {
  989                         cm = mtod(control, struct cmsghdr *);
  990                         if (control->m_len < sizeof(*cm) || cm->cmsg_len == 0
  991                             || cm->cmsg_len > control->m_len) {
  992                                 error = EINVAL;
  993                                 break;
  994                         }
  995                         if (cm->cmsg_level != IPPROTO_IP)
  996                                 continue;
  997 
  998                         switch (cm->cmsg_type) {
  999                         case IP_SENDSRCADDR:
 1000                                 if (cm->cmsg_len !=
 1001                                     CMSG_LEN(sizeof(struct in_addr))) {
 1002                                         error = EINVAL;
 1003                                         break;
 1004                                 }
 1005                                 bzero(&src, sizeof(src));
 1006                                 src.sin_family = AF_INET;
 1007                                 src.sin_len = sizeof(src);
 1008                                 src.sin_port = inp->inp_lport;
 1009                                 src.sin_addr =
 1010                                     *(struct in_addr *)CMSG_DATA(cm);
 1011                                 break;
 1012 
 1013                         case IP_TOS:
 1014                                 if (cm->cmsg_len != CMSG_LEN(sizeof(u_char))) {
 1015                                         error = EINVAL;
 1016                                         break;
 1017                                 }
 1018                                 tos = *(u_char *)CMSG_DATA(cm);
 1019                                 break;
 1020 
 1021                         default:
 1022                                 error = ENOPROTOOPT;
 1023                                 break;
 1024                         }
 1025                         if (error)
 1026                                 break;
 1027                 }
 1028                 m_freem(control);
 1029         }
 1030         if (error) {
 1031                 INP_RUNLOCK(inp);
 1032                 m_freem(m);
 1033                 return (error);
 1034         }
 1035 
 1036         /*
 1037          * Depending on whether or not the application has bound or connected
 1038          * the socket, we may have to do varying levels of work.  The optimal
 1039          * case is for a connected UDP socket, as a global lock isn't
 1040          * required at all.
 1041          *
 1042          * In order to decide which we need, we require stability of the
 1043          * inpcb binding, which we ensure by acquiring a read lock on the
 1044          * inpcb.  This doesn't strictly follow the lock order, so we play
 1045          * the trylock and retry game; note that we may end up with more
 1046          * conservative locks than required the second time around, so later
 1047          * assertions have to accept that.  Further analysis of the number of
 1048          * misses under contention is required.
 1049          *
 1050          * XXXRW: Check that hash locking update here is correct.
 1051          */
 1052         sin = (struct sockaddr_in *)addr;
 1053         if (sin != NULL &&
 1054             (inp->inp_laddr.s_addr == INADDR_ANY && inp->inp_lport == 0)) {
 1055                 INP_RUNLOCK(inp);
 1056                 INP_WLOCK(inp);
 1057                 INP_HASH_WLOCK(&V_udbinfo);
 1058                 unlock_udbinfo = UH_WLOCKED;
 1059         } else if ((sin != NULL && (
 1060             (sin->sin_addr.s_addr == INADDR_ANY) ||
 1061             (sin->sin_addr.s_addr == INADDR_BROADCAST) ||
 1062             (inp->inp_laddr.s_addr == INADDR_ANY) ||
 1063             (inp->inp_lport == 0))) ||
 1064             (src.sin_family == AF_INET)) {
 1065                 INP_HASH_RLOCK(&V_udbinfo);
 1066                 unlock_udbinfo = UH_RLOCKED;
 1067         } else
 1068                 unlock_udbinfo = UH_UNLOCKED;
 1069 
 1070         /*
 1071          * If the IP_SENDSRCADDR control message was specified, override the
 1072          * source address for this datagram.  Its use is invalidated if the
 1073          * address thus specified is incomplete or clobbers other inpcbs.
 1074          */
 1075         laddr = inp->inp_laddr;
 1076         lport = inp->inp_lport;
 1077         if (src.sin_family == AF_INET) {
 1078                 INP_HASH_LOCK_ASSERT(&V_udbinfo);
 1079                 if ((lport == 0) ||
 1080                     (laddr.s_addr == INADDR_ANY &&
 1081                      src.sin_addr.s_addr == INADDR_ANY)) {
 1082                         error = EINVAL;
 1083                         goto release;
 1084                 }
 1085                 error = in_pcbbind_setup(inp, (struct sockaddr *)&src,
 1086                     &laddr.s_addr, &lport, td->td_ucred);
 1087                 if (error)
 1088                         goto release;
 1089         }
 1090 
 1091         /*
 1092          * If a UDP socket has been connected, then a local address/port will
 1093          * have been selected and bound.
 1094          *
 1095          * If a UDP socket has not been connected to, then an explicit
 1096          * destination address must be used, in which case a local
 1097          * address/port may not have been selected and bound.
 1098          */
 1099         if (sin != NULL) {
 1100                 INP_LOCK_ASSERT(inp);
 1101                 if (inp->inp_faddr.s_addr != INADDR_ANY) {
 1102                         error = EISCONN;
 1103                         goto release;
 1104                 }
 1105 
 1106                 /*
 1107                  * Jail may rewrite the destination address, so let it do
 1108                  * that before we use it.
 1109                  */
 1110                 error = prison_remote_ip4(td->td_ucred, &sin->sin_addr);
 1111                 if (error)
 1112                         goto release;
 1113 
 1114                 /*
 1115                  * If a local address or port hasn't yet been selected, or if
 1116                  * the destination address needs to be rewritten due to using
 1117                  * a special INADDR_ constant, invoke in_pcbconnect_setup()
 1118                  * to do the heavy lifting.  Once a port is selected, we
 1119                  * commit the binding back to the socket; we also commit the
 1120                  * binding of the address if in jail.
 1121                  *
 1122                  * If we already have a valid binding and we're not
 1123                  * requesting a destination address rewrite, use a fast path.
 1124                  */
 1125                 if (inp->inp_laddr.s_addr == INADDR_ANY ||
 1126                     inp->inp_lport == 0 ||
 1127                     sin->sin_addr.s_addr == INADDR_ANY ||
 1128                     sin->sin_addr.s_addr == INADDR_BROADCAST) {
 1129                         INP_HASH_LOCK_ASSERT(&V_udbinfo);
 1130                         error = in_pcbconnect_setup(inp, addr, &laddr.s_addr,
 1131                             &lport, &faddr.s_addr, &fport, NULL,
 1132                             td->td_ucred);
 1133                         if (error)
 1134                                 goto release;
 1135 
 1136                         /*
 1137                          * XXXRW: Why not commit the port if the address is
 1138                          * !INADDR_ANY?
 1139                          */
 1140                         /* Commit the local port if newly assigned. */
 1141                         if (inp->inp_laddr.s_addr == INADDR_ANY &&
 1142                             inp->inp_lport == 0) {
 1143                                 INP_WLOCK_ASSERT(inp);
 1144                                 INP_HASH_WLOCK_ASSERT(&V_udbinfo);
 1145                                 /*
 1146                                  * Remember addr if jailed, to prevent
 1147                                  * rebinding.
 1148                                  */
 1149                                 if (prison_flag(td->td_ucred, PR_IP4))
 1150                                         inp->inp_laddr = laddr;
 1151                                 inp->inp_lport = lport;
 1152                                 if (in_pcbinshash(inp) != 0) {
 1153                                         inp->inp_lport = 0;
 1154                                         error = EAGAIN;
 1155                                         goto release;
 1156                                 }
 1157                                 inp->inp_flags |= INP_ANONPORT;
 1158                         }
 1159                 } else {
 1160                         faddr = sin->sin_addr;
 1161                         fport = sin->sin_port;
 1162                 }
 1163         } else {
 1164                 INP_LOCK_ASSERT(inp);
 1165                 faddr = inp->inp_faddr;
 1166                 fport = inp->inp_fport;
 1167                 if (faddr.s_addr == INADDR_ANY) {
 1168                         error = ENOTCONN;
 1169                         goto release;
 1170                 }
 1171         }
 1172 
 1173         /*
 1174          * Calculate data length and get a mbuf for UDP, IP, and possible
 1175          * link-layer headers.  Immediate slide the data pointer back forward
 1176          * since we won't use that space at this layer.
 1177          */
 1178         M_PREPEND(m, sizeof(struct udpiphdr) + max_linkhdr, M_DONTWAIT);
 1179         if (m == NULL) {
 1180                 error = ENOBUFS;
 1181                 goto release;
 1182         }
 1183         m->m_data += max_linkhdr;
 1184         m->m_len -= max_linkhdr;
 1185         m->m_pkthdr.len -= max_linkhdr;
 1186 
 1187         /*
 1188          * Fill in mbuf with extended UDP header and addresses and length put
 1189          * into network format.
 1190          */
 1191         ui = mtod(m, struct udpiphdr *);
 1192         bzero(ui->ui_x1, sizeof(ui->ui_x1));    /* XXX still needed? */
 1193         ui->ui_pr = IPPROTO_UDP;
 1194         ui->ui_src = laddr;
 1195         ui->ui_dst = faddr;
 1196         ui->ui_sport = lport;
 1197         ui->ui_dport = fport;
 1198         ui->ui_ulen = htons((u_short)len + sizeof(struct udphdr));
 1199 
 1200         /*
 1201          * Set the Don't Fragment bit in the IP header.
 1202          */
 1203         if (inp->inp_flags & INP_DONTFRAG) {
 1204                 struct ip *ip;
 1205 
 1206                 ip = (struct ip *)&ui->ui_i;
 1207                 ip->ip_off |= IP_DF;
 1208         }
 1209 
 1210         ipflags = 0;
 1211         if (inp->inp_socket->so_options & SO_DONTROUTE)
 1212                 ipflags |= IP_ROUTETOIF;
 1213         if (inp->inp_socket->so_options & SO_BROADCAST)
 1214                 ipflags |= IP_ALLOWBROADCAST;
 1215         if (inp->inp_flags & INP_ONESBCAST)
 1216                 ipflags |= IP_SENDONES;
 1217 
 1218 #ifdef MAC
 1219         mac_inpcb_create_mbuf(inp, m);
 1220 #endif
 1221 
 1222         /*
 1223          * Set up checksum and output datagram.
 1224          */
 1225         if (V_udp_cksum) {
 1226                 if (inp->inp_flags & INP_ONESBCAST)
 1227                         faddr.s_addr = INADDR_BROADCAST;
 1228                 ui->ui_sum = in_pseudo(ui->ui_src.s_addr, faddr.s_addr,
 1229                     htons((u_short)len + sizeof(struct udphdr) + IPPROTO_UDP));
 1230                 m->m_pkthdr.csum_flags = CSUM_UDP;
 1231                 m->m_pkthdr.csum_data = offsetof(struct udphdr, uh_sum);
 1232         } else
 1233                 ui->ui_sum = 0;
 1234         ((struct ip *)ui)->ip_len = sizeof (struct udpiphdr) + len;
 1235         ((struct ip *)ui)->ip_ttl = inp->inp_ip_ttl;    /* XXX */
 1236         ((struct ip *)ui)->ip_tos = tos;                /* XXX */
 1237         UDPSTAT_INC(udps_opackets);
 1238 
 1239         if (unlock_udbinfo == UH_WLOCKED)
 1240                 INP_HASH_WUNLOCK(&V_udbinfo);
 1241         else if (unlock_udbinfo == UH_RLOCKED)
 1242                 INP_HASH_RUNLOCK(&V_udbinfo);
 1243         error = ip_output(m, inp->inp_options, NULL, ipflags,
 1244             inp->inp_moptions, inp);
 1245         if (unlock_udbinfo == UH_WLOCKED)
 1246                 INP_WUNLOCK(inp);
 1247         else
 1248                 INP_RUNLOCK(inp);
 1249         return (error);
 1250 
 1251 release:
 1252         if (unlock_udbinfo == UH_WLOCKED) {
 1253                 INP_HASH_WUNLOCK(&V_udbinfo);
 1254                 INP_WUNLOCK(inp);
 1255         } else if (unlock_udbinfo == UH_RLOCKED) {
 1256                 INP_HASH_RUNLOCK(&V_udbinfo);
 1257                 INP_RUNLOCK(inp);
 1258         } else
 1259                 INP_RUNLOCK(inp);
 1260         m_freem(m);
 1261         return (error);
 1262 }
 1263 
 1264 
 1265 #if defined(IPSEC) && defined(IPSEC_NAT_T)
 1266 /*
 1267  * Potentially decap ESP in UDP frame.  Check for an ESP header
 1268  * and optional marker; if present, strip the UDP header and
 1269  * push the result through IPSec.
 1270  *
 1271  * Returns mbuf to be processed (potentially re-allocated) or
 1272  * NULL if consumed and/or processed.
 1273  */
 1274 static struct mbuf *
 1275 udp4_espdecap(struct inpcb *inp, struct mbuf *m, int off)
 1276 {
 1277         size_t minlen, payload, skip, iphlen;
 1278         caddr_t data;
 1279         struct udpcb *up;
 1280         struct m_tag *tag;
 1281         struct udphdr *udphdr;
 1282         struct ip *ip;
 1283 
 1284         INP_RLOCK_ASSERT(inp);
 1285 
 1286         /* 
 1287          * Pull up data so the longest case is contiguous:
 1288          *    IP/UDP hdr + non ESP marker + ESP hdr.
 1289          */
 1290         minlen = off + sizeof(uint64_t) + sizeof(struct esp);
 1291         if (minlen > m->m_pkthdr.len)
 1292                 minlen = m->m_pkthdr.len;
 1293         if ((m = m_pullup(m, minlen)) == NULL) {
 1294                 IPSECSTAT_INC(in_inval);
 1295                 return (NULL);          /* Bypass caller processing. */
 1296         }
 1297         data = mtod(m, caddr_t);        /* Points to ip header. */
 1298         payload = m->m_len - off;       /* Size of payload. */
 1299 
 1300         if (payload == 1 && data[off] == '\xff')
 1301                 return (m);             /* NB: keepalive packet, no decap. */
 1302 
 1303         up = intoudpcb(inp);
 1304         KASSERT(up != NULL, ("%s: udpcb NULL", __func__));
 1305         KASSERT((up->u_flags & UF_ESPINUDP_ALL) != 0,
 1306             ("u_flags 0x%x", up->u_flags));
 1307 
 1308         /* 
 1309          * Check that the payload is large enough to hold an
 1310          * ESP header and compute the amount of data to remove.
 1311          *
 1312          * NB: the caller has already done a pullup for us.
 1313          * XXX can we assume alignment and eliminate bcopys?
 1314          */
 1315         if (up->u_flags & UF_ESPINUDP_NON_IKE) {
 1316                 /*
 1317                  * draft-ietf-ipsec-nat-t-ike-0[01].txt and
 1318                  * draft-ietf-ipsec-udp-encaps-(00/)01.txt, ignoring
 1319                  * possible AH mode non-IKE marker+non-ESP marker
 1320                  * from draft-ietf-ipsec-udp-encaps-00.txt.
 1321                  */
 1322                 uint64_t marker;
 1323 
 1324                 if (payload <= sizeof(uint64_t) + sizeof(struct esp))
 1325                         return (m);     /* NB: no decap. */
 1326                 bcopy(data + off, &marker, sizeof(uint64_t));
 1327                 if (marker != 0)        /* Non-IKE marker. */
 1328                         return (m);     /* NB: no decap. */
 1329                 skip = sizeof(uint64_t) + sizeof(struct udphdr);
 1330         } else {
 1331                 uint32_t spi;
 1332 
 1333                 if (payload <= sizeof(struct esp)) {
 1334                         IPSECSTAT_INC(in_inval);
 1335                         m_freem(m);
 1336                         return (NULL);  /* Discard. */
 1337                 }
 1338                 bcopy(data + off, &spi, sizeof(uint32_t));
 1339                 if (spi == 0)           /* Non-ESP marker. */
 1340                         return (m);     /* NB: no decap. */
 1341                 skip = sizeof(struct udphdr);
 1342         }
 1343 
 1344         /*
 1345          * Setup a PACKET_TAG_IPSEC_NAT_T_PORT tag to remember
 1346          * the UDP ports. This is required if we want to select
 1347          * the right SPD for multiple hosts behind same NAT.
 1348          *
 1349          * NB: ports are maintained in network byte order everywhere
 1350          *     in the NAT-T code.
 1351          */
 1352         tag = m_tag_get(PACKET_TAG_IPSEC_NAT_T_PORTS,
 1353                 2 * sizeof(uint16_t), M_NOWAIT);
 1354         if (tag == NULL) {
 1355                 IPSECSTAT_INC(in_nomem);
 1356                 m_freem(m);
 1357                 return (NULL);          /* Discard. */
 1358         }
 1359         iphlen = off - sizeof(struct udphdr);
 1360         udphdr = (struct udphdr *)(data + iphlen);
 1361         ((uint16_t *)(tag + 1))[0] = udphdr->uh_sport;
 1362         ((uint16_t *)(tag + 1))[1] = udphdr->uh_dport;
 1363         m_tag_prepend(m, tag);
 1364 
 1365         /*
 1366          * Remove the UDP header (and possibly the non ESP marker)
 1367          * IP header length is iphlen
 1368          * Before:
 1369          *   <--- off --->
 1370          *   +----+------+-----+
 1371          *   | IP |  UDP | ESP |
 1372          *   +----+------+-----+
 1373          *        <-skip->
 1374          * After:
 1375          *          +----+-----+
 1376          *          | IP | ESP |
 1377          *          +----+-----+
 1378          *   <-skip->
 1379          */
 1380         ovbcopy(data, data + skip, iphlen);
 1381         m_adj(m, skip);
 1382 
 1383         ip = mtod(m, struct ip *);
 1384         ip->ip_len -= skip;
 1385         ip->ip_p = IPPROTO_ESP;
 1386 
 1387         /*
 1388          * We cannot yet update the cksums so clear any
 1389          * h/w cksum flags as they are no longer valid.
 1390          */
 1391         if (m->m_pkthdr.csum_flags & CSUM_DATA_VALID)
 1392                 m->m_pkthdr.csum_flags &= ~(CSUM_DATA_VALID|CSUM_PSEUDO_HDR);
 1393 
 1394         (void) ipsec4_common_input(m, iphlen, ip->ip_p);
 1395         return (NULL);                  /* NB: consumed, bypass processing. */
 1396 }
 1397 #endif /* defined(IPSEC) && defined(IPSEC_NAT_T) */
 1398 
 1399 static void
 1400 udp_abort(struct socket *so)
 1401 {
 1402         struct inpcb *inp;
 1403 
 1404         inp = sotoinpcb(so);
 1405         KASSERT(inp != NULL, ("udp_abort: inp == NULL"));
 1406         INP_WLOCK(inp);
 1407         if (inp->inp_faddr.s_addr != INADDR_ANY) {
 1408                 INP_HASH_WLOCK(&V_udbinfo);
 1409                 in_pcbdisconnect(inp);
 1410                 inp->inp_laddr.s_addr = INADDR_ANY;
 1411                 INP_HASH_WUNLOCK(&V_udbinfo);
 1412                 soisdisconnected(so);
 1413         }
 1414         INP_WUNLOCK(inp);
 1415 }
 1416 
 1417 static int
 1418 udp_attach(struct socket *so, int proto, struct thread *td)
 1419 {
 1420         struct inpcb *inp;
 1421         int error;
 1422 
 1423         inp = sotoinpcb(so);
 1424         KASSERT(inp == NULL, ("udp_attach: inp != NULL"));
 1425         error = soreserve(so, udp_sendspace, udp_recvspace);
 1426         if (error)
 1427                 return (error);
 1428         INP_INFO_WLOCK(&V_udbinfo);
 1429         error = in_pcballoc(so, &V_udbinfo);
 1430         if (error) {
 1431                 INP_INFO_WUNLOCK(&V_udbinfo);
 1432                 return (error);
 1433         }
 1434 
 1435         inp = sotoinpcb(so);
 1436         inp->inp_vflag |= INP_IPV4;
 1437         inp->inp_ip_ttl = V_ip_defttl;
 1438 
 1439         error = udp_newudpcb(inp);
 1440         if (error) {
 1441                 in_pcbdetach(inp);
 1442                 in_pcbfree(inp);
 1443                 INP_INFO_WUNLOCK(&V_udbinfo);
 1444                 return (error);
 1445         }
 1446 
 1447         INP_WUNLOCK(inp);
 1448         INP_INFO_WUNLOCK(&V_udbinfo);
 1449         return (0);
 1450 }
 1451 #endif /* INET */
 1452 
 1453 int
 1454 udp_set_kernel_tunneling(struct socket *so, udp_tun_func_t f)
 1455 {
 1456         struct inpcb *inp;
 1457         struct udpcb *up;
 1458 
 1459         KASSERT(so->so_type == SOCK_DGRAM,
 1460             ("udp_set_kernel_tunneling: !dgram"));
 1461         inp = sotoinpcb(so);
 1462         KASSERT(inp != NULL, ("udp_set_kernel_tunneling: inp == NULL"));
 1463         INP_WLOCK(inp);
 1464         up = intoudpcb(inp);
 1465         if (up->u_tun_func != NULL) {
 1466                 INP_WUNLOCK(inp);
 1467                 return (EBUSY);
 1468         }
 1469         up->u_tun_func = f;
 1470         INP_WUNLOCK(inp);
 1471         return (0);
 1472 }
 1473 
 1474 #ifdef INET
 1475 static int
 1476 udp_bind(struct socket *so, struct sockaddr *nam, struct thread *td)
 1477 {
 1478         struct inpcb *inp;
 1479         int error;
 1480 
 1481         inp = sotoinpcb(so);
 1482         KASSERT(inp != NULL, ("udp_bind: inp == NULL"));
 1483         INP_WLOCK(inp);
 1484         INP_HASH_WLOCK(&V_udbinfo);
 1485         error = in_pcbbind(inp, nam, td->td_ucred);
 1486         INP_HASH_WUNLOCK(&V_udbinfo);
 1487         INP_WUNLOCK(inp);
 1488         return (error);
 1489 }
 1490 
 1491 static void
 1492 udp_close(struct socket *so)
 1493 {
 1494         struct inpcb *inp;
 1495 
 1496         inp = sotoinpcb(so);
 1497         KASSERT(inp != NULL, ("udp_close: inp == NULL"));
 1498         INP_WLOCK(inp);
 1499         if (inp->inp_faddr.s_addr != INADDR_ANY) {
 1500                 INP_HASH_WLOCK(&V_udbinfo);
 1501                 in_pcbdisconnect(inp);
 1502                 inp->inp_laddr.s_addr = INADDR_ANY;
 1503                 INP_HASH_WUNLOCK(&V_udbinfo);
 1504                 soisdisconnected(so);
 1505         }
 1506         INP_WUNLOCK(inp);
 1507 }
 1508 
 1509 static int
 1510 udp_connect(struct socket *so, struct sockaddr *nam, struct thread *td)
 1511 {
 1512         struct inpcb *inp;
 1513         int error;
 1514         struct sockaddr_in *sin;
 1515 
 1516         inp = sotoinpcb(so);
 1517         KASSERT(inp != NULL, ("udp_connect: inp == NULL"));
 1518         INP_WLOCK(inp);
 1519         if (inp->inp_faddr.s_addr != INADDR_ANY) {
 1520                 INP_WUNLOCK(inp);
 1521                 return (EISCONN);
 1522         }
 1523         sin = (struct sockaddr_in *)nam;
 1524         error = prison_remote_ip4(td->td_ucred, &sin->sin_addr);
 1525         if (error != 0) {
 1526                 INP_WUNLOCK(inp);
 1527                 return (error);
 1528         }
 1529         INP_HASH_WLOCK(&V_udbinfo);
 1530         error = in_pcbconnect(inp, nam, td->td_ucred);
 1531         INP_HASH_WUNLOCK(&V_udbinfo);
 1532         if (error == 0)
 1533                 soisconnected(so);
 1534         INP_WUNLOCK(inp);
 1535         return (error);
 1536 }
 1537 
 1538 static void
 1539 udp_detach(struct socket *so)
 1540 {
 1541         struct inpcb *inp;
 1542         struct udpcb *up;
 1543 
 1544         inp = sotoinpcb(so);
 1545         KASSERT(inp != NULL, ("udp_detach: inp == NULL"));
 1546         KASSERT(inp->inp_faddr.s_addr == INADDR_ANY,
 1547             ("udp_detach: not disconnected"));
 1548         INP_INFO_WLOCK(&V_udbinfo);
 1549         INP_WLOCK(inp);
 1550         up = intoudpcb(inp);
 1551         KASSERT(up != NULL, ("%s: up == NULL", __func__));
 1552         inp->inp_ppcb = NULL;
 1553         in_pcbdetach(inp);
 1554         in_pcbfree(inp);
 1555         INP_INFO_WUNLOCK(&V_udbinfo);
 1556         udp_discardcb(up);
 1557 }
 1558 
 1559 static int
 1560 udp_disconnect(struct socket *so)
 1561 {
 1562         struct inpcb *inp;
 1563 
 1564         inp = sotoinpcb(so);
 1565         KASSERT(inp != NULL, ("udp_disconnect: inp == NULL"));
 1566         INP_WLOCK(inp);
 1567         if (inp->inp_faddr.s_addr == INADDR_ANY) {
 1568                 INP_WUNLOCK(inp);
 1569                 return (ENOTCONN);
 1570         }
 1571         INP_HASH_WLOCK(&V_udbinfo);
 1572         in_pcbdisconnect(inp);
 1573         inp->inp_laddr.s_addr = INADDR_ANY;
 1574         INP_HASH_WUNLOCK(&V_udbinfo);
 1575         SOCK_LOCK(so);
 1576         so->so_state &= ~SS_ISCONNECTED;                /* XXX */
 1577         SOCK_UNLOCK(so);
 1578         INP_WUNLOCK(inp);
 1579         return (0);
 1580 }
 1581 
 1582 static int
 1583 udp_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *addr,
 1584     struct mbuf *control, struct thread *td)
 1585 {
 1586         struct inpcb *inp;
 1587 
 1588         inp = sotoinpcb(so);
 1589         KASSERT(inp != NULL, ("udp_send: inp == NULL"));
 1590         return (udp_output(inp, m, addr, control, td));
 1591 }
 1592 #endif /* INET */
 1593 
 1594 int
 1595 udp_shutdown(struct socket *so)
 1596 {
 1597         struct inpcb *inp;
 1598 
 1599         inp = sotoinpcb(so);
 1600         KASSERT(inp != NULL, ("udp_shutdown: inp == NULL"));
 1601         INP_WLOCK(inp);
 1602         socantsendmore(so);
 1603         INP_WUNLOCK(inp);
 1604         return (0);
 1605 }
 1606 
 1607 #ifdef INET
 1608 struct pr_usrreqs udp_usrreqs = {
 1609         .pru_abort =            udp_abort,
 1610         .pru_attach =           udp_attach,
 1611         .pru_bind =             udp_bind,
 1612         .pru_connect =          udp_connect,
 1613         .pru_control =          in_control,
 1614         .pru_detach =           udp_detach,
 1615         .pru_disconnect =       udp_disconnect,
 1616         .pru_peeraddr =         in_getpeeraddr,
 1617         .pru_send =             udp_send,
 1618         .pru_soreceive =        soreceive_dgram,
 1619         .pru_sosend =           sosend_dgram,
 1620         .pru_shutdown =         udp_shutdown,
 1621         .pru_sockaddr =         in_getsockaddr,
 1622         .pru_sosetlabel =       in_pcbsosetlabel,
 1623         .pru_close =            udp_close,
 1624 };
 1625 #endif /* INET */

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