lwip_ip4.c

00001 /**
00002  * @file
00003  * This is the IPv4 layer implementation for incoming and outgoing IP traffic.
00004  *
00005  * @see ip_frag.c
00006  *
00007  */
00008 
00009 /*
00010  * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
00011  * All rights reserved.
00012  *
00013  * Redistribution and use in source and binary forms, with or without modification,
00014  * are permitted provided that the following conditions are met:
00015  *
00016  * 1. Redistributions of source code must retain the above copyright notice,
00017  *    this list of conditions and the following disclaimer.
00018  * 2. Redistributions in binary form must reproduce the above copyright notice,
00019  *    this list of conditions and the following disclaimer in the documentation
00020  *    and/or other materials provided with the distribution.
00021  * 3. The name of the author may not be used to endorse or promote products
00022  *    derived from this software without specific prior written permission.
00023  *
00024  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
00025  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
00026  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
00027  * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
00028  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
00029  * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
00030  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
00031  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
00032  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
00033  * OF SUCH DAMAGE.
00034  *
00035  * This file is part of the lwIP TCP/IP stack.
00036  *
00037  * Author: Adam Dunkels <adam@sics.se>
00038  *
00039  */
00040 
00041 #include "lwip/opt.h"
00042 
00043 #if LWIP_IPV4
00044 
00045 #include "lwip/ip.h"
00046 #include "lwip/def.h"
00047 #include "lwip/mem.h"
00048 #include "lwip/ip4_frag.h"
00049 #include "lwip/inet_chksum.h"
00050 #include "lwip/netif.h"
00051 #include "lwip/icmp.h"
00052 #include "lwip/igmp.h"
00053 #include "lwip/raw.h"
00054 #include "lwip/udp.h"
00055 #include "lwip/priv/tcp_priv.h"
00056 #include "lwip/autoip.h"
00057 #include "lwip/stats.h"
00058 #include "lwip/prot/dhcp.h"
00059 
00060 #include <string.h>
00061 
00062 #ifdef LWIP_HOOK_FILENAME
00063 #include LWIP_HOOK_FILENAME
00064 #endif
00065 
00066 /** Set this to 0 in the rare case of wanting to call an extra function to
00067  * generate the IP checksum (in contrast to calculating it on-the-fly). */
00068 #ifndef LWIP_INLINE_IP_CHKSUM
00069 #if LWIP_CHECKSUM_CTRL_PER_NETIF
00070 #define LWIP_INLINE_IP_CHKSUM   0
00071 #else /* LWIP_CHECKSUM_CTRL_PER_NETIF */
00072 #define LWIP_INLINE_IP_CHKSUM   1
00073 #endif /* LWIP_CHECKSUM_CTRL_PER_NETIF */
00074 #endif
00075 
00076 #if LWIP_INLINE_IP_CHKSUM && CHECKSUM_GEN_IP
00077 #define CHECKSUM_GEN_IP_INLINE  1
00078 #else
00079 #define CHECKSUM_GEN_IP_INLINE  0
00080 #endif
00081 
00082 #if LWIP_DHCP || defined(LWIP_IP_ACCEPT_UDP_PORT)
00083 #define IP_ACCEPT_LINK_LAYER_ADDRESSING 1
00084 
00085 /** Some defines for DHCP to let link-layer-addressed packets through while the
00086  * netif is down.
00087  * To use this in your own application/protocol, define LWIP_IP_ACCEPT_UDP_PORT(port)
00088  * to return 1 if the port is accepted and 0 if the port is not accepted.
00089  */
00090 #if LWIP_DHCP && defined(LWIP_IP_ACCEPT_UDP_PORT)
00091 /* accept DHCP client port and custom port */
00092 #define IP_ACCEPT_LINK_LAYER_ADDRESSED_PORT(port) (((port) == PP_NTOHS(DHCP_CLIENT_PORT)) \
00093          || (LWIP_IP_ACCEPT_UDP_PORT(port)))
00094 #elif defined(LWIP_IP_ACCEPT_UDP_PORT) /* LWIP_DHCP && defined(LWIP_IP_ACCEPT_UDP_PORT) */
00095 /* accept custom port only */
00096 #define IP_ACCEPT_LINK_LAYER_ADDRESSED_PORT(port) (LWIP_IP_ACCEPT_UDP_PORT(port))
00097 #else /* LWIP_DHCP && defined(LWIP_IP_ACCEPT_UDP_PORT) */
00098 /* accept DHCP client port only */
00099 #define IP_ACCEPT_LINK_LAYER_ADDRESSED_PORT(port) ((port) == PP_NTOHS(DHCP_CLIENT_PORT))
00100 #endif /* LWIP_DHCP && defined(LWIP_IP_ACCEPT_UDP_PORT) */
00101 
00102 #else /* LWIP_DHCP */
00103 #define IP_ACCEPT_LINK_LAYER_ADDRESSING 0
00104 #endif /* LWIP_DHCP */
00105 
00106 /** The IP header ID of the next outgoing IP packet */
00107 static u16_t ip_id;
00108 
00109 #if LWIP_MULTICAST_TX_OPTIONS
00110 /** The default netif used for multicast */
00111 static struct netif* ip4_default_multicast_netif;
00112 
00113 /**
00114  * @ingroup ip4
00115  * Set a default netif for IPv4 multicast. */
00116 void
00117 ip4_set_default_multicast_netif(struct netif* default_multicast_netif)
00118 {
00119   ip4_default_multicast_netif = default_multicast_netif;
00120 }
00121 #endif /* LWIP_MULTICAST_TX_OPTIONS */
00122 
00123 #ifdef LWIP_HOOK_IP4_ROUTE_SRC
00124 /**
00125  * Source based IPv4 routing must be fully implemented in
00126  * LWIP_HOOK_IP4_ROUTE_SRC(). This function only provides he parameters.
00127  */
00128 struct netif *
00129 ip4_route_src(const ip4_addr_t *dest, const ip4_addr_t *src)
00130 {
00131   if (src != NULL) {
00132     /* when src==NULL, the hook is called from ip4_route(dest) */
00133     struct netif *netif = LWIP_HOOK_IP4_ROUTE_SRC(dest, src);
00134     if (netif != NULL) {
00135       return netif;
00136     }
00137   }
00138   return ip4_route(dest);
00139 }
00140 #endif /* LWIP_HOOK_IP4_ROUTE_SRC */
00141 
00142 /**
00143  * Finds the appropriate network interface for a given IP address. It
00144  * searches the list of network interfaces linearly. A match is found
00145  * if the masked IP address of the network interface equals the masked
00146  * IP address given to the function.
00147  *
00148  * @param dest the destination IP address for which to find the route
00149  * @return the netif on which to send to reach dest
00150  */
00151 struct netif *
00152 ip4_route(const ip4_addr_t *dest)
00153 {
00154   struct netif *netif;
00155 
00156 #if LWIP_MULTICAST_TX_OPTIONS
00157   /* Use administratively selected interface for multicast by default */
00158   if (ip4_addr_ismulticast(dest) && ip4_default_multicast_netif) {
00159     return ip4_default_multicast_netif;
00160   }
00161 #endif /* LWIP_MULTICAST_TX_OPTIONS */
00162 
00163   /* iterate through netifs */
00164   for (netif = netif_list; netif != NULL; netif = netif->next) {
00165     /* is the netif up, does it have a link and a valid address? */
00166     if (netif_is_up(netif) && netif_is_link_up(netif) && !ip4_addr_isany_val(*netif_ip4_addr(netif))) {
00167       /* network mask matches? */
00168       if (ip4_addr_netcmp(dest, netif_ip4_addr(netif), netif_ip4_netmask(netif))) {
00169         /* return netif on which to forward IP packet */
00170         return netif;
00171       }
00172       /* gateway matches on a non broadcast interface? (i.e. peer in a point to point interface) */
00173       if (((netif->flags & NETIF_FLAG_BROADCAST) == 0) && ip4_addr_cmp(dest, netif_ip4_gw(netif))) {
00174         /* return netif on which to forward IP packet */
00175         return netif;
00176       }
00177     }
00178   }
00179 
00180 #if LWIP_NETIF_LOOPBACK && !LWIP_HAVE_LOOPIF
00181   /* loopif is disabled, looopback traffic is passed through any netif */
00182   if (ip4_addr_isloopback(dest)) {
00183     /* don't check for link on loopback traffic */
00184     if (netif_default != NULL && netif_is_up(netif_default)) {
00185       return netif_default;
00186     }
00187     /* default netif is not up, just use any netif for loopback traffic */
00188     for (netif = netif_list; netif != NULL; netif = netif->next) {
00189       if (netif_is_up(netif)) {
00190         return netif;
00191       }
00192     }
00193     return NULL;
00194   }
00195 #endif /* LWIP_NETIF_LOOPBACK && !LWIP_HAVE_LOOPIF */
00196 
00197 #ifdef LWIP_HOOK_IP4_ROUTE_SRC
00198   netif = LWIP_HOOK_IP4_ROUTE_SRC(dest, NULL);
00199   if (netif != NULL) {
00200     return netif;
00201   }
00202 #elif defined(LWIP_HOOK_IP4_ROUTE)
00203   netif = LWIP_HOOK_IP4_ROUTE(dest);
00204   if (netif != NULL) {
00205     return netif;
00206   }
00207 #endif
00208 
00209   if ((netif_default == NULL) || !netif_is_up(netif_default) || !netif_is_link_up(netif_default) ||
00210       ip4_addr_isany_val(*netif_ip4_addr(netif_default))) {
00211     /* No matching netif found and default netif is not usable.
00212        If this is not good enough for you, use LWIP_HOOK_IP4_ROUTE() */
00213     LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("ip4_route: No route to %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
00214       ip4_addr1_16(dest), ip4_addr2_16(dest), ip4_addr3_16(dest), ip4_addr4_16(dest)));
00215     IP_STATS_INC(ip.rterr);
00216     MIB2_STATS_INC(mib2.ipoutnoroutes);
00217     return NULL;
00218   }
00219 
00220   return netif_default;
00221 }
00222 
00223 #if IP_FORWARD
00224 /**
00225  * Determine whether an IP address is in a reserved set of addresses
00226  * that may not be forwarded, or whether datagrams to that destination
00227  * may be forwarded.
00228  * @param p the packet to forward
00229  * @return 1: can forward 0: discard
00230  */
00231 static int
00232 ip4_canforward(struct pbuf *p)
00233 {
00234   u32_t addr = lwip_htonl(ip4_addr_get_u32(ip4_current_dest_addr()));
00235 
00236   if (p->flags & PBUF_FLAG_LLBCAST) {
00237     /* don't route link-layer broadcasts */
00238     return 0;
00239   }
00240   if ((p->flags & PBUF_FLAG_LLMCAST) && !IP_MULTICAST(addr)) {
00241     /* don't route link-layer multicasts unless the destination address is an IP
00242        multicast address */
00243     return 0;
00244   }
00245   if (IP_EXPERIMENTAL(addr)) {
00246     return 0;
00247   }
00248   if (IP_CLASSA(addr)) {
00249     u32_t net = addr & IP_CLASSA_NET;
00250     if ((net == 0) || (net == ((u32_t)IP_LOOPBACKNET << IP_CLASSA_NSHIFT))) {
00251       /* don't route loopback packets */
00252       return 0;
00253     }
00254   }
00255   return 1;
00256 }
00257 
00258 /**
00259  * Forwards an IP packet. It finds an appropriate route for the
00260  * packet, decrements the TTL value of the packet, adjusts the
00261  * checksum and outputs the packet on the appropriate interface.
00262  *
00263  * @param p the packet to forward (p->payload points to IP header)
00264  * @param iphdr the IP header of the input packet
00265  * @param inp the netif on which this packet was received
00266  */
00267 static void
00268 ip4_forward(struct pbuf *p, struct ip_hdr *iphdr, struct netif *inp)
00269 {
00270   struct netif *netif;
00271 
00272   PERF_START;
00273   LWIP_UNUSED_ARG(inp);
00274 
00275   if (!ip4_canforward(p)) {
00276     goto return_noroute;
00277   }
00278 
00279   /* RFC3927 2.7: do not forward link-local addresses */
00280   if (ip4_addr_islinklocal(ip4_current_dest_addr())) {
00281     LWIP_DEBUGF(IP_DEBUG, ("ip4_forward: not forwarding LLA %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
00282       ip4_addr1_16(ip4_current_dest_addr()), ip4_addr2_16(ip4_current_dest_addr()),
00283       ip4_addr3_16(ip4_current_dest_addr()), ip4_addr4_16(ip4_current_dest_addr())));
00284     goto return_noroute;
00285   }
00286 
00287   /* Find network interface where to forward this IP packet to. */
00288   netif = ip4_route_src(ip4_current_dest_addr(), ip4_current_src_addr());
00289   if (netif == NULL) {
00290     LWIP_DEBUGF(IP_DEBUG, ("ip4_forward: no forwarding route for %"U16_F".%"U16_F".%"U16_F".%"U16_F" found\n",
00291       ip4_addr1_16(ip4_current_dest_addr()), ip4_addr2_16(ip4_current_dest_addr()),
00292       ip4_addr3_16(ip4_current_dest_addr()), ip4_addr4_16(ip4_current_dest_addr())));
00293     /* @todo: send ICMP_DUR_NET? */
00294     goto return_noroute;
00295   }
00296 #if !IP_FORWARD_ALLOW_TX_ON_RX_NETIF
00297   /* Do not forward packets onto the same network interface on which
00298    * they arrived. */
00299   if (netif == inp) {
00300     LWIP_DEBUGF(IP_DEBUG, ("ip4_forward: not bouncing packets back on incoming interface.\n"));
00301     goto return_noroute;
00302   }
00303 #endif /* IP_FORWARD_ALLOW_TX_ON_RX_NETIF */
00304 
00305   /* decrement TTL */
00306   IPH_TTL_SET(iphdr, IPH_TTL(iphdr) - 1);
00307   /* send ICMP if TTL == 0 */
00308   if (IPH_TTL(iphdr) == 0) {
00309     MIB2_STATS_INC(mib2.ipinhdrerrors);
00310 #if LWIP_ICMP
00311     /* Don't send ICMP messages in response to ICMP messages */
00312     if (IPH_PROTO(iphdr) != IP_PROTO_ICMP) {
00313       icmp_time_exceeded(p, ICMP_TE_TTL);
00314     }
00315 #endif /* LWIP_ICMP */
00316     return;
00317   }
00318 
00319   /* Incrementally update the IP checksum. */
00320   if (IPH_CHKSUM(iphdr) >= PP_HTONS(0xffffU - 0x100)) {
00321     IPH_CHKSUM_SET(iphdr, IPH_CHKSUM(iphdr) + PP_HTONS(0x100) + 1);
00322   } else {
00323     IPH_CHKSUM_SET(iphdr, IPH_CHKSUM(iphdr) + PP_HTONS(0x100));
00324   }
00325 
00326   LWIP_DEBUGF(IP_DEBUG, ("ip4_forward: forwarding packet to %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
00327     ip4_addr1_16(ip4_current_dest_addr()), ip4_addr2_16(ip4_current_dest_addr()),
00328     ip4_addr3_16(ip4_current_dest_addr()), ip4_addr4_16(ip4_current_dest_addr())));
00329 
00330   IP_STATS_INC(ip.fw);
00331   MIB2_STATS_INC(mib2.ipforwdatagrams);
00332   IP_STATS_INC(ip.xmit);
00333 
00334   PERF_STOP("ip4_forward");
00335   /* don't fragment if interface has mtu set to 0 [loopif] */
00336   if (netif->mtu && (p->tot_len > netif->mtu)) {
00337     if ((IPH_OFFSET(iphdr) & PP_NTOHS(IP_DF)) == 0) {
00338 #if IP_FRAG
00339       ip4_frag(p, netif, ip4_current_dest_addr());
00340 #else /* IP_FRAG */
00341       /* @todo: send ICMP Destination Unreachable code 13 "Communication administratively prohibited"? */
00342 #endif /* IP_FRAG */
00343     } else {
00344 #if LWIP_ICMP
00345       /* send ICMP Destination Unreachable code 4: "Fragmentation Needed and DF Set" */
00346       icmp_dest_unreach(p, ICMP_DUR_FRAG);
00347 #endif /* LWIP_ICMP */
00348     }
00349     return;
00350   }
00351   /* transmit pbuf on chosen interface */
00352   netif->output(netif, p, ip4_current_dest_addr());
00353   return;
00354 return_noroute:
00355   MIB2_STATS_INC(mib2.ipoutnoroutes);
00356 }
00357 #endif /* IP_FORWARD */
00358 
00359 /**
00360  * This function is called by the network interface device driver when
00361  * an IP packet is received. The function does the basic checks of the
00362  * IP header such as packet size being at least larger than the header
00363  * size etc. If the packet was not destined for us, the packet is
00364  * forwarded (using ip_forward). The IP checksum is always checked.
00365  *
00366  * Finally, the packet is sent to the upper layer protocol input function.
00367  *
00368  * @param p the received IP packet (p->payload points to IP header)
00369  * @param inp the netif on which this packet was received
00370  * @return ERR_OK if the packet was processed (could return ERR_* if it wasn't
00371  *         processed, but currently always returns ERR_OK)
00372  */
00373 err_t
00374 ip4_input(struct pbuf *p, struct netif *inp)
00375 {
00376   struct ip_hdr *iphdr;
00377   struct netif *netif;
00378   u16_t iphdr_hlen;
00379   u16_t iphdr_len;
00380 #if IP_ACCEPT_LINK_LAYER_ADDRESSING || LWIP_IGMP
00381   int check_ip_src = 1;
00382 #endif /* IP_ACCEPT_LINK_LAYER_ADDRESSING || LWIP_IGMP */
00383 
00384   IP_STATS_INC(ip.recv);
00385   MIB2_STATS_INC(mib2.ipinreceives);
00386 
00387   /* identify the IP header */
00388   iphdr = (struct ip_hdr *)p->payload;
00389   if (IPH_V(iphdr) != 4) {
00390     LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_WARNING, ("IP packet dropped due to bad version number %"U16_F"\n", (u16_t)IPH_V(iphdr)));
00391     ip4_debug_print(p);
00392     pbuf_free(p);
00393     IP_STATS_INC(ip.err);
00394     IP_STATS_INC(ip.drop);
00395     MIB2_STATS_INC(mib2.ipinhdrerrors);
00396     return ERR_OK;
00397   }
00398 
00399 #ifdef LWIP_HOOK_IP4_INPUT
00400   if (LWIP_HOOK_IP4_INPUT(p, inp)) {
00401     /* the packet has been eaten */
00402     return ERR_OK;
00403   }
00404 #endif
00405 
00406   /* obtain IP header length in number of 32-bit words */
00407   iphdr_hlen = IPH_HL(iphdr);
00408   /* calculate IP header length in bytes */
00409   iphdr_hlen *= 4;
00410   /* obtain ip length in bytes */
00411   iphdr_len = lwip_ntohs(IPH_LEN(iphdr));
00412 
00413   /* Trim pbuf. This is especially required for packets < 60 bytes. */
00414   if (iphdr_len < p->tot_len) {
00415     pbuf_realloc(p, iphdr_len);
00416   }
00417 
00418   /* header length exceeds first pbuf length, or ip length exceeds total pbuf length? */
00419   if ((iphdr_hlen > p->len) || (iphdr_len > p->tot_len) || (iphdr_hlen < IP_HLEN)) {
00420     if (iphdr_hlen < IP_HLEN) {
00421       LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
00422         ("ip4_input: short IP header (%"U16_F" bytes) received, IP packet dropped\n", iphdr_hlen));
00423     }
00424     if (iphdr_hlen > p->len) {
00425       LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
00426         ("IP header (len %"U16_F") does not fit in first pbuf (len %"U16_F"), IP packet dropped.\n",
00427         iphdr_hlen, p->len));
00428     }
00429     if (iphdr_len > p->tot_len) {
00430       LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
00431         ("IP (len %"U16_F") is longer than pbuf (len %"U16_F"), IP packet dropped.\n",
00432         iphdr_len, p->tot_len));
00433     }
00434     /* free (drop) packet pbufs */
00435     pbuf_free(p);
00436     IP_STATS_INC(ip.lenerr);
00437     IP_STATS_INC(ip.drop);
00438     MIB2_STATS_INC(mib2.ipindiscards);
00439     return ERR_OK;
00440   }
00441 
00442   /* verify checksum */
00443 #if CHECKSUM_CHECK_IP
00444   IF__NETIF_CHECKSUM_ENABLED(inp, NETIF_CHECKSUM_CHECK_IP) {
00445     if (inet_chksum(iphdr, iphdr_hlen) != 0) {
00446 
00447       LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
00448         ("Checksum (0x%"X16_F") failed, IP packet dropped.\n", inet_chksum(iphdr, iphdr_hlen)));
00449       ip4_debug_print(p);
00450       pbuf_free(p);
00451       IP_STATS_INC(ip.chkerr);
00452       IP_STATS_INC(ip.drop);
00453       MIB2_STATS_INC(mib2.ipinhdrerrors);
00454       return ERR_OK;
00455     }
00456   }
00457 #endif
00458 
00459   /* copy IP addresses to aligned ip_addr_t */
00460   ip_addr_copy_from_ip4(ip_data.current_iphdr_dest, iphdr->dest);
00461   ip_addr_copy_from_ip4(ip_data.current_iphdr_src, iphdr->src);
00462 
00463   /* match packet against an interface, i.e. is this packet for us? */
00464   if (ip4_addr_ismulticast(ip4_current_dest_addr())) {
00465 #if LWIP_IGMP
00466     if ((inp->flags & NETIF_FLAG_IGMP) && (igmp_lookfor_group(inp, ip4_current_dest_addr()))) {
00467       /* IGMP snooping switches need 0.0.0.0 to be allowed as source address (RFC 4541) */
00468       ip4_addr_t allsystems;
00469       IP4_ADDR(&allsystems, 224, 0, 0, 1);
00470       if (ip4_addr_cmp(ip4_current_dest_addr(), &allsystems) &&
00471           ip4_addr_isany(ip4_current_src_addr())) {
00472         check_ip_src = 0;
00473       }
00474       netif = inp;
00475     } else {
00476       netif = NULL;
00477     }
00478 #else /* LWIP_IGMP */
00479     if ((netif_is_up(inp)) && (!ip4_addr_isany_val(*netif_ip4_addr(inp)))) {
00480       netif = inp;
00481     } else {
00482       netif = NULL;
00483     }
00484 #endif /* LWIP_IGMP */
00485   } else {
00486     /* start trying with inp. if that's not acceptable, start walking the
00487        list of configured netifs.
00488        'first' is used as a boolean to mark whether we started walking the list */
00489     int first = 1;
00490     netif = inp;
00491     do {
00492       LWIP_DEBUGF(IP_DEBUG, ("ip_input: iphdr->dest 0x%"X32_F" netif->ip_addr 0x%"X32_F" (0x%"X32_F", 0x%"X32_F", 0x%"X32_F")\n",
00493           ip4_addr_get_u32(&iphdr->dest), ip4_addr_get_u32(netif_ip4_addr(netif)),
00494           ip4_addr_get_u32(&iphdr->dest) & ip4_addr_get_u32(netif_ip4_netmask(netif)),
00495           ip4_addr_get_u32(netif_ip4_addr(netif)) & ip4_addr_get_u32(netif_ip4_netmask(netif)),
00496           ip4_addr_get_u32(&iphdr->dest) & ~ip4_addr_get_u32(netif_ip4_netmask(netif))));
00497 
00498       /* interface is up and configured? */
00499       if ((netif_is_up(netif)) && (!ip4_addr_isany_val(*netif_ip4_addr(netif)))) {
00500         /* unicast to this interface address? */
00501         if (ip4_addr_cmp(ip4_current_dest_addr(), netif_ip4_addr(netif)) ||
00502             /* or broadcast on this interface network address? */
00503             ip4_addr_isbroadcast(ip4_current_dest_addr(), netif)
00504 #if LWIP_NETIF_LOOPBACK && !LWIP_HAVE_LOOPIF
00505             || (ip4_addr_get_u32(ip4_current_dest_addr()) == PP_HTONL(IPADDR_LOOPBACK))
00506 #endif /* LWIP_NETIF_LOOPBACK && !LWIP_HAVE_LOOPIF */
00507             ) {
00508           LWIP_DEBUGF(IP_DEBUG, ("ip4_input: packet accepted on interface %c%c\n",
00509               netif->name[0], netif->name[1]));
00510           /* break out of for loop */
00511           break;
00512         }
00513 #if LWIP_AUTOIP
00514         /* connections to link-local addresses must persist after changing
00515            the netif's address (RFC3927 ch. 1.9) */
00516         if (autoip_accept_packet(netif, ip4_current_dest_addr())) {
00517           LWIP_DEBUGF(IP_DEBUG, ("ip4_input: LLA packet accepted on interface %c%c\n",
00518               netif->name[0], netif->name[1]));
00519           /* break out of for loop */
00520           break;
00521         }
00522 #endif /* LWIP_AUTOIP */
00523       }
00524       if (first) {
00525 #if !LWIP_NETIF_LOOPBACK || LWIP_HAVE_LOOPIF
00526         /* Packets sent to the loopback address must not be accepted on an
00527          * interface that does not have the loopback address assigned to it,
00528          * unless a non-loopback interface is used for loopback traffic. */
00529         if (ip4_addr_isloopback(ip4_current_dest_addr())) {
00530           netif = NULL;
00531           break;
00532         }
00533 #endif /* !LWIP_NETIF_LOOPBACK || LWIP_HAVE_LOOPIF */
00534         first = 0;
00535         netif = netif_list;
00536       } else {
00537         netif = netif->next;
00538       }
00539       if (netif == inp) {
00540         netif = netif->next;
00541       }
00542     } while (netif != NULL);
00543   }
00544 
00545 #if IP_ACCEPT_LINK_LAYER_ADDRESSING
00546   /* Pass DHCP messages regardless of destination address. DHCP traffic is addressed
00547    * using link layer addressing (such as Ethernet MAC) so we must not filter on IP.
00548    * According to RFC 1542 section 3.1.1, referred by RFC 2131).
00549    *
00550    * If you want to accept private broadcast communication while a netif is down,
00551    * define LWIP_IP_ACCEPT_UDP_PORT(dst_port), e.g.:
00552    *
00553    * #define LWIP_IP_ACCEPT_UDP_PORT(dst_port) ((dst_port) == PP_NTOHS(12345))
00554    */
00555   if (netif == NULL) {
00556     /* remote port is DHCP server? */
00557     if (IPH_PROTO(iphdr) == IP_PROTO_UDP) {
00558       struct udp_hdr *udphdr = (struct udp_hdr *)((u8_t *)iphdr + iphdr_hlen);
00559       LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_TRACE, ("ip4_input: UDP packet to DHCP client port %"U16_F"\n",
00560         lwip_ntohs(udphdr->dest)));
00561       if (IP_ACCEPT_LINK_LAYER_ADDRESSED_PORT(udphdr->dest)) {
00562         LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_TRACE, ("ip4_input: DHCP packet accepted.\n"));
00563         netif = inp;
00564         check_ip_src = 0;
00565       }
00566     }
00567   }
00568 #endif /* IP_ACCEPT_LINK_LAYER_ADDRESSING */
00569 
00570   /* broadcast or multicast packet source address? Compliant with RFC 1122: 3.2.1.3 */
00571 #if LWIP_IGMP || IP_ACCEPT_LINK_LAYER_ADDRESSING
00572   if (check_ip_src
00573 #if IP_ACCEPT_LINK_LAYER_ADDRESSING
00574   /* DHCP servers need 0.0.0.0 to be allowed as source address (RFC 1.1.2.2: 3.2.1.3/a) */
00575       && !ip4_addr_isany_val(*ip4_current_src_addr())
00576 #endif /* IP_ACCEPT_LINK_LAYER_ADDRESSING */
00577      )
00578 #endif /* LWIP_IGMP || IP_ACCEPT_LINK_LAYER_ADDRESSING */
00579   {
00580     if ((ip4_addr_isbroadcast(ip4_current_src_addr(), inp)) ||
00581         (ip4_addr_ismulticast(ip4_current_src_addr()))) {
00582       /* packet source is not valid */
00583       LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_WARNING, ("ip4_input: packet source is not valid.\n"));
00584       /* free (drop) packet pbufs */
00585       pbuf_free(p);
00586       IP_STATS_INC(ip.drop);
00587       MIB2_STATS_INC(mib2.ipinaddrerrors);
00588       MIB2_STATS_INC(mib2.ipindiscards);
00589       return ERR_OK;
00590     }
00591   }
00592 
00593   /* packet not for us? */
00594   if (netif == NULL) {
00595     /* packet not for us, route or discard */
00596     LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_TRACE, ("ip4_input: packet not for us.\n"));
00597 #if IP_FORWARD
00598     /* non-broadcast packet? */
00599     if (!ip4_addr_isbroadcast(ip4_current_dest_addr(), inp)) {
00600       /* try to forward IP packet on (other) interfaces */
00601       ip4_forward(p, iphdr, inp);
00602     } else
00603 #endif /* IP_FORWARD */
00604     {
00605       IP_STATS_INC(ip.drop);
00606       MIB2_STATS_INC(mib2.ipinaddrerrors);
00607       MIB2_STATS_INC(mib2.ipindiscards);
00608     }
00609     pbuf_free(p);
00610     return ERR_OK;
00611   }
00612   /* packet consists of multiple fragments? */
00613   if ((IPH_OFFSET(iphdr) & PP_HTONS(IP_OFFMASK | IP_MF)) != 0) {
00614 #if IP_REASSEMBLY /* packet fragment reassembly code present? */
00615     LWIP_DEBUGF(IP_DEBUG, ("IP packet is a fragment (id=0x%04"X16_F" tot_len=%"U16_F" len=%"U16_F" MF=%"U16_F" offset=%"U16_F"), calling ip4_reass()\n",
00616       lwip_ntohs(IPH_ID(iphdr)), p->tot_len, lwip_ntohs(IPH_LEN(iphdr)), (u16_t)!!(IPH_OFFSET(iphdr) & PP_HTONS(IP_MF)), (u16_t)((lwip_ntohs(IPH_OFFSET(iphdr)) & IP_OFFMASK)*8)));
00617     /* reassemble the packet*/
00618     p = ip4_reass(p);
00619     /* packet not fully reassembled yet? */
00620     if (p == NULL) {
00621       return ERR_OK;
00622     }
00623     iphdr = (struct ip_hdr *)p->payload;
00624 #else /* IP_REASSEMBLY == 0, no packet fragment reassembly code present */
00625     pbuf_free(p);
00626     LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("IP packet dropped since it was fragmented (0x%"X16_F") (while IP_REASSEMBLY == 0).\n",
00627       lwip_ntohs(IPH_OFFSET(iphdr))));
00628     IP_STATS_INC(ip.opterr);
00629     IP_STATS_INC(ip.drop);
00630     /* unsupported protocol feature */
00631     MIB2_STATS_INC(mib2.ipinunknownprotos);
00632     return ERR_OK;
00633 #endif /* IP_REASSEMBLY */
00634   }
00635 
00636 #if IP_OPTIONS_ALLOWED == 0 /* no support for IP options in the IP header? */
00637 
00638 #if LWIP_IGMP
00639   /* there is an extra "router alert" option in IGMP messages which we allow for but do not police */
00640   if ((iphdr_hlen > IP_HLEN) &&  (IPH_PROTO(iphdr) != IP_PROTO_IGMP)) {
00641 #else
00642   if (iphdr_hlen > IP_HLEN) {
00643 #endif /* LWIP_IGMP */
00644     LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("IP packet dropped since there were IP options (while IP_OPTIONS_ALLOWED == 0).\n"));
00645     pbuf_free(p);
00646     IP_STATS_INC(ip.opterr);
00647     IP_STATS_INC(ip.drop);
00648     /* unsupported protocol feature */
00649     MIB2_STATS_INC(mib2.ipinunknownprotos);
00650     return ERR_OK;
00651   }
00652 #endif /* IP_OPTIONS_ALLOWED == 0 */
00653 
00654   /* send to upper layers */
00655   LWIP_DEBUGF(IP_DEBUG, ("ip4_input: \n"));
00656   ip4_debug_print(p);
00657   LWIP_DEBUGF(IP_DEBUG, ("ip4_input: p->len %"U16_F" p->tot_len %"U16_F"\n", p->len, p->tot_len));
00658 
00659   ip_data.current_netif = netif;
00660   ip_data.current_input_netif = inp;
00661   ip_data.current_ip4_header = iphdr;
00662   ip_data.current_ip_header_tot_len = IPH_HL(iphdr) * 4;
00663 
00664 #if LWIP_RAW
00665   /* raw input did not eat the packet? */
00666   if (raw_input(p, inp) == 0)
00667 #endif /* LWIP_RAW */
00668   {
00669     pbuf_header(p, -(s16_t)iphdr_hlen); /* Move to payload, no check necessary. */
00670 
00671     switch (IPH_PROTO(iphdr)) {
00672 #if LWIP_UDP
00673     case IP_PROTO_UDP:
00674 #if LWIP_UDPLITE
00675     case IP_PROTO_UDPLITE:
00676 #endif /* LWIP_UDPLITE */
00677       MIB2_STATS_INC(mib2.ipindelivers);
00678       udp_input(p, inp);
00679       break;
00680 #endif /* LWIP_UDP */
00681 #if LWIP_TCP
00682     case IP_PROTO_TCP:
00683       MIB2_STATS_INC(mib2.ipindelivers);
00684       tcp_input(p, inp);
00685       break;
00686 #endif /* LWIP_TCP */
00687 #if LWIP_ICMP
00688     case IP_PROTO_ICMP:
00689       MIB2_STATS_INC(mib2.ipindelivers);
00690       icmp_input(p, inp);
00691       break;
00692 #endif /* LWIP_ICMP */
00693 #if LWIP_IGMP
00694     case IP_PROTO_IGMP:
00695       igmp_input(p, inp, ip4_current_dest_addr());
00696       break;
00697 #endif /* LWIP_IGMP */
00698     default:
00699 #if LWIP_ICMP
00700       /* send ICMP destination protocol unreachable unless is was a broadcast */
00701       if (!ip4_addr_isbroadcast(ip4_current_dest_addr(), netif) &&
00702           !ip4_addr_ismulticast(ip4_current_dest_addr())) {
00703         pbuf_header_force(p, iphdr_hlen); /* Move to ip header, no check necessary. */
00704         p->payload = iphdr;
00705         icmp_dest_unreach(p, ICMP_DUR_PROTO);
00706       }
00707 #endif /* LWIP_ICMP */
00708       pbuf_free(p);
00709 
00710       LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("Unsupported transport protocol %"U16_F"\n", (u16_t)IPH_PROTO(iphdr)));
00711 
00712       IP_STATS_INC(ip.proterr);
00713       IP_STATS_INC(ip.drop);
00714       MIB2_STATS_INC(mib2.ipinunknownprotos);
00715     }
00716   }
00717 
00718   /* @todo: this is not really necessary... */
00719   ip_data.current_netif = NULL;
00720   ip_data.current_input_netif = NULL;
00721   ip_data.current_ip4_header = NULL;
00722   ip_data.current_ip_header_tot_len = 0;
00723   ip4_addr_set_any(ip4_current_src_addr());
00724   ip4_addr_set_any(ip4_current_dest_addr());
00725 
00726   return ERR_OK;
00727 }
00728 
00729 /**
00730  * Sends an IP packet on a network interface. This function constructs
00731  * the IP header and calculates the IP header checksum. If the source
00732  * IP address is NULL, the IP address of the outgoing network
00733  * interface is filled in as source address.
00734  * If the destination IP address is LWIP_IP_HDRINCL, p is assumed to already
00735  * include an IP header and p->payload points to it instead of the data.
00736  *
00737  * @param p the packet to send (p->payload points to the data, e.g. next
00738             protocol header; if dest == LWIP_IP_HDRINCL, p already includes an
00739             IP header and p->payload points to that IP header)
00740  * @param src the source IP address to send from (if src == IP4_ADDR_ANY, the
00741  *         IP  address of the netif used to send is used as source address)
00742  * @param dest the destination IP address to send the packet to
00743  * @param ttl the TTL value to be set in the IP header
00744  * @param tos the TOS value to be set in the IP header
00745  * @param proto the PROTOCOL to be set in the IP header
00746  * @param netif the netif on which to send this packet
00747  * @return ERR_OK if the packet was sent OK
00748  *         ERR_BUF if p doesn't have enough space for IP/LINK headers
00749  *         returns errors returned by netif->output
00750  *
00751  * @note ip_id: RFC791 "some host may be able to simply use
00752  *  unique identifiers independent of destination"
00753  */
00754 err_t
00755 ip4_output_if(struct pbuf *p, const ip4_addr_t *src, const ip4_addr_t *dest,
00756              u8_t ttl, u8_t tos,
00757              u8_t proto, struct netif *netif)
00758 {
00759 #if IP_OPTIONS_SEND
00760   return ip4_output_if_opt(p, src, dest, ttl, tos, proto, netif, NULL, 0);
00761 }
00762 
00763 /**
00764  * Same as ip_output_if() but with the possibility to include IP options:
00765  *
00766  * @ param ip_options pointer to the IP options, copied into the IP header
00767  * @ param optlen length of ip_options
00768  */
00769 err_t
00770 ip4_output_if_opt(struct pbuf *p, const ip4_addr_t *src, const ip4_addr_t *dest,
00771        u8_t ttl, u8_t tos, u8_t proto, struct netif *netif, void *ip_options,
00772        u16_t optlen)
00773 {
00774 #endif /* IP_OPTIONS_SEND */
00775   const ip4_addr_t *src_used = src;
00776   if (dest != LWIP_IP_HDRINCL) {
00777     if (ip4_addr_isany(src)) {
00778       src_used = netif_ip4_addr(netif);
00779     }
00780   }
00781 
00782 #if IP_OPTIONS_SEND
00783   return ip4_output_if_opt_src(p, src_used, dest, ttl, tos, proto, netif,
00784     ip_options, optlen);
00785 #else /* IP_OPTIONS_SEND */
00786   return ip4_output_if_src(p, src_used, dest, ttl, tos, proto, netif);
00787 #endif /* IP_OPTIONS_SEND */
00788 }
00789 
00790 /**
00791  * Same as ip_output_if() but 'src' address is not replaced by netif address
00792  * when it is 'any'.
00793  */
00794 err_t
00795 ip4_output_if_src(struct pbuf *p, const ip4_addr_t *src, const ip4_addr_t *dest,
00796              u8_t ttl, u8_t tos,
00797              u8_t proto, struct netif *netif)
00798 {
00799 #if IP_OPTIONS_SEND
00800   return ip4_output_if_opt_src(p, src, dest, ttl, tos, proto, netif, NULL, 0);
00801 }
00802 
00803 /**
00804  * Same as ip_output_if_opt() but 'src' address is not replaced by netif address
00805  * when it is 'any'.
00806  */
00807 err_t
00808 ip4_output_if_opt_src(struct pbuf *p, const ip4_addr_t *src, const ip4_addr_t *dest,
00809        u8_t ttl, u8_t tos, u8_t proto, struct netif *netif, void *ip_options,
00810        u16_t optlen)
00811 {
00812 #endif /* IP_OPTIONS_SEND */
00813   struct ip_hdr *iphdr;
00814   ip4_addr_t dest_addr;
00815 #if CHECKSUM_GEN_IP_INLINE
00816   u32_t chk_sum = 0;
00817 #endif /* CHECKSUM_GEN_IP_INLINE */
00818 
00819   LWIP_IP_CHECK_PBUF_REF_COUNT_FOR_TX(p);
00820 
00821   MIB2_STATS_INC(mib2.ipoutrequests);
00822 
00823   /* Should the IP header be generated or is it already included in p? */
00824   if (dest != LWIP_IP_HDRINCL) {
00825     u16_t ip_hlen = IP_HLEN;
00826 #if IP_OPTIONS_SEND
00827     u16_t optlen_aligned = 0;
00828     if (optlen != 0) {
00829 #if CHECKSUM_GEN_IP_INLINE
00830       int i;
00831 #endif /* CHECKSUM_GEN_IP_INLINE */
00832       /* round up to a multiple of 4 */
00833       optlen_aligned = ((optlen + 3) & ~3);
00834       ip_hlen += optlen_aligned;
00835       /* First write in the IP options */
00836       if (pbuf_header(p, optlen_aligned)) {
00837         LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("ip4_output_if_opt: not enough room for IP options in pbuf\n"));
00838         IP_STATS_INC(ip.err);
00839         MIB2_STATS_INC(mib2.ipoutdiscards);
00840         return ERR_BUF;
00841       }
00842       MEMCPY(p->payload, ip_options, optlen);
00843       if (optlen < optlen_aligned) {
00844         /* zero the remaining bytes */
00845         memset(((char*)p->payload) + optlen, 0, optlen_aligned - optlen);
00846       }
00847 #if CHECKSUM_GEN_IP_INLINE
00848       for (i = 0; i < optlen_aligned/2; i++) {
00849         chk_sum += ((u16_t*)p->payload)[i];
00850       }
00851 #endif /* CHECKSUM_GEN_IP_INLINE */
00852     }
00853 #endif /* IP_OPTIONS_SEND */
00854     /* generate IP header */
00855     if (pbuf_header(p, IP_HLEN)) {
00856       LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("ip4_output: not enough room for IP header in pbuf\n"));
00857 
00858       IP_STATS_INC(ip.err);
00859       MIB2_STATS_INC(mib2.ipoutdiscards);
00860       return ERR_BUF;
00861     }
00862 
00863     iphdr = (struct ip_hdr *)p->payload;
00864     LWIP_ASSERT("check that first pbuf can hold struct ip_hdr",
00865                (p->len >= sizeof(struct ip_hdr)));
00866 
00867     IPH_TTL_SET(iphdr, ttl);
00868     IPH_PROTO_SET(iphdr, proto);
00869 #if CHECKSUM_GEN_IP_INLINE
00870     chk_sum += PP_NTOHS(proto | (ttl << 8));
00871 #endif /* CHECKSUM_GEN_IP_INLINE */
00872 
00873     /* dest cannot be NULL here */
00874     ip4_addr_copy(iphdr->dest, *dest);
00875 #if CHECKSUM_GEN_IP_INLINE
00876     chk_sum += ip4_addr_get_u32(&iphdr->dest) & 0xFFFF;
00877     chk_sum += ip4_addr_get_u32(&iphdr->dest) >> 16;
00878 #endif /* CHECKSUM_GEN_IP_INLINE */
00879 
00880     IPH_VHL_SET(iphdr, 4, ip_hlen / 4);
00881     IPH_TOS_SET(iphdr, tos);
00882 #if CHECKSUM_GEN_IP_INLINE
00883     chk_sum += PP_NTOHS(tos | (iphdr->_v_hl << 8));
00884 #endif /* CHECKSUM_GEN_IP_INLINE */
00885     IPH_LEN_SET(iphdr, lwip_htons(p->tot_len));
00886 #if CHECKSUM_GEN_IP_INLINE
00887     chk_sum += iphdr->_len;
00888 #endif /* CHECKSUM_GEN_IP_INLINE */
00889     IPH_OFFSET_SET(iphdr, 0);
00890     IPH_ID_SET(iphdr, lwip_htons(ip_id));
00891 #if CHECKSUM_GEN_IP_INLINE
00892     chk_sum += iphdr->_id;
00893 #endif /* CHECKSUM_GEN_IP_INLINE */
00894     ++ip_id;
00895 
00896     if (src == NULL) {
00897       ip4_addr_copy(iphdr->src, *IP4_ADDR_ANY4);
00898     } else {
00899       /* src cannot be NULL here */
00900       ip4_addr_copy(iphdr->src, *src);
00901     }
00902 
00903 #if CHECKSUM_GEN_IP_INLINE
00904     chk_sum += ip4_addr_get_u32(&iphdr->src) & 0xFFFF;
00905     chk_sum += ip4_addr_get_u32(&iphdr->src) >> 16;
00906     chk_sum = (chk_sum >> 16) + (chk_sum & 0xFFFF);
00907     chk_sum = (chk_sum >> 16) + chk_sum;
00908     chk_sum = ~chk_sum;
00909     IF__NETIF_CHECKSUM_ENABLED(netif, NETIF_CHECKSUM_GEN_IP) {
00910       iphdr->_chksum = (u16_t)chk_sum; /* network order */
00911     }
00912 #if LWIP_CHECKSUM_CTRL_PER_NETIF
00913     else {
00914       IPH_CHKSUM_SET(iphdr, 0);
00915     }
00916 #endif /* LWIP_CHECKSUM_CTRL_PER_NETIF*/
00917 #else /* CHECKSUM_GEN_IP_INLINE */
00918     IPH_CHKSUM_SET(iphdr, 0);
00919 #if CHECKSUM_GEN_IP
00920     IF__NETIF_CHECKSUM_ENABLED(netif, NETIF_CHECKSUM_GEN_IP) {
00921       IPH_CHKSUM_SET(iphdr, inet_chksum(iphdr, ip_hlen));
00922     }
00923 #endif /* CHECKSUM_GEN_IP */
00924 #endif /* CHECKSUM_GEN_IP_INLINE */
00925   } else {
00926     /* IP header already included in p */
00927     iphdr = (struct ip_hdr *)p->payload;
00928     ip4_addr_copy(dest_addr, iphdr->dest);
00929     dest = &dest_addr;
00930   }
00931 
00932   IP_STATS_INC(ip.xmit);
00933 
00934   LWIP_DEBUGF(IP_DEBUG, ("ip4_output_if: %c%c%"U16_F"\n", netif->name[0], netif->name[1], (u16_t)netif->num));
00935   ip4_debug_print(p);
00936 
00937 #if ENABLE_LOOPBACK
00938   if (ip4_addr_cmp(dest, netif_ip4_addr(netif))
00939 #if !LWIP_HAVE_LOOPIF
00940       || ip4_addr_isloopback(dest)
00941 #endif /* !LWIP_HAVE_LOOPIF */
00942       ) {
00943     /* Packet to self, enqueue it for loopback */
00944     LWIP_DEBUGF(IP_DEBUG, ("netif_loop_output()"));
00945     return netif_loop_output(netif, p);
00946   }
00947 #if LWIP_MULTICAST_TX_OPTIONS
00948   if ((p->flags & PBUF_FLAG_MCASTLOOP) != 0) {
00949     netif_loop_output(netif, p);
00950   }
00951 #endif /* LWIP_MULTICAST_TX_OPTIONS */
00952 #endif /* ENABLE_LOOPBACK */
00953 #if IP_FRAG
00954   /* don't fragment if interface has mtu set to 0 [loopif] */
00955   if (netif->mtu && (p->tot_len > netif->mtu)) {
00956     return ip4_frag(p, netif, dest);
00957   }
00958 #endif /* IP_FRAG */
00959 
00960   LWIP_DEBUGF(IP_DEBUG, ("ip4_output_if: call netif->output()\n"));
00961   return netif->output(netif, p, dest);
00962 }
00963 
00964 /**
00965  * Simple interface to ip_output_if. It finds the outgoing network
00966  * interface and calls upon ip_output_if to do the actual work.
00967  *
00968  * @param p the packet to send (p->payload points to the data, e.g. next
00969             protocol header; if dest == LWIP_IP_HDRINCL, p already includes an
00970             IP header and p->payload points to that IP header)
00971  * @param src the source IP address to send from (if src == IP4_ADDR_ANY, the
00972  *         IP  address of the netif used to send is used as source address)
00973  * @param dest the destination IP address to send the packet to
00974  * @param ttl the TTL value to be set in the IP header
00975  * @param tos the TOS value to be set in the IP header
00976  * @param proto the PROTOCOL to be set in the IP header
00977  *
00978  * @return ERR_RTE if no route is found
00979  *         see ip_output_if() for more return values
00980  */
00981 err_t
00982 ip4_output(struct pbuf *p, const ip4_addr_t *src, const ip4_addr_t *dest,
00983           u8_t ttl, u8_t tos, u8_t proto)
00984 {
00985   struct netif *netif;
00986 
00987   LWIP_IP_CHECK_PBUF_REF_COUNT_FOR_TX(p);
00988 
00989   if ((netif = ip4_route_src(dest, src)) == NULL) {
00990     LWIP_DEBUGF(IP_DEBUG, ("ip4_output: No route to %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
00991       ip4_addr1_16(dest), ip4_addr2_16(dest), ip4_addr3_16(dest), ip4_addr4_16(dest)));
00992     IP_STATS_INC(ip.rterr);
00993     return ERR_RTE;
00994   }
00995 
00996   return ip4_output_if(p, src, dest, ttl, tos, proto, netif);
00997 }
00998 
00999 #if LWIP_NETIF_HWADDRHINT
01000 /** Like ip_output, but takes and addr_hint pointer that is passed on to netif->addr_hint
01001  *  before calling ip_output_if.
01002  *
01003  * @param p the packet to send (p->payload points to the data, e.g. next
01004             protocol header; if dest == LWIP_IP_HDRINCL, p already includes an
01005             IP header and p->payload points to that IP header)
01006  * @param src the source IP address to send from (if src == IP4_ADDR_ANY, the
01007  *         IP  address of the netif used to send is used as source address)
01008  * @param dest the destination IP address to send the packet to
01009  * @param ttl the TTL value to be set in the IP header
01010  * @param tos the TOS value to be set in the IP header
01011  * @param proto the PROTOCOL to be set in the IP header
01012  * @param addr_hint address hint pointer set to netif->addr_hint before
01013  *        calling ip_output_if()
01014  *
01015  * @return ERR_RTE if no route is found
01016  *         see ip_output_if() for more return values
01017  */
01018 err_t
01019 ip4_output_hinted(struct pbuf *p, const ip4_addr_t *src, const ip4_addr_t *dest,
01020           u8_t ttl, u8_t tos, u8_t proto, u8_t *addr_hint)
01021 {
01022   struct netif *netif;
01023   err_t err;
01024 
01025   LWIP_IP_CHECK_PBUF_REF_COUNT_FOR_TX(p);
01026 
01027   if ((netif = ip4_route_src(dest, src)) == NULL) {
01028     LWIP_DEBUGF(IP_DEBUG, ("ip4_output: No route to %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
01029       ip4_addr1_16(dest), ip4_addr2_16(dest), ip4_addr3_16(dest), ip4_addr4_16(dest)));
01030     IP_STATS_INC(ip.rterr);
01031     return ERR_RTE;
01032   }
01033 
01034   NETIF_SET_HWADDRHINT(netif, addr_hint);
01035   err = ip4_output_if(p, src, dest, ttl, tos, proto, netif);
01036   NETIF_SET_HWADDRHINT(netif, NULL);
01037 
01038   return err;
01039 }
01040 #endif /* LWIP_NETIF_HWADDRHINT*/
01041 
01042 #if IP_DEBUG
01043 /* Print an IP header by using LWIP_DEBUGF
01044  * @param p an IP packet, p->payload pointing to the IP header
01045  */
01046 void
01047 ip4_debug_print(struct pbuf *p)
01048 {
01049   struct ip_hdr *iphdr = (struct ip_hdr *)p->payload;
01050 
01051   TRACE_TO_ASCII_HEX_DUMPF("IP>", lwip_ntohs(IPH_LEN(iphdr)), (char *) iphdr);
01052 
01053   LWIP_DEBUGF(IP_DEBUG, ("IP header:\n"));
01054   LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
01055   LWIP_DEBUGF(IP_DEBUG, ("|%2"S16_F" |%2"S16_F" |  0x%02"X16_F" |     %5"U16_F"     | (v, hl, tos, len)\n",
01056                     (u16_t)IPH_V(iphdr),
01057                     (u16_t)IPH_HL(iphdr),
01058                     (u16_t)IPH_TOS(iphdr),
01059                     lwip_ntohs(IPH_LEN(iphdr))));
01060   LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
01061   LWIP_DEBUGF(IP_DEBUG, ("|    %5"U16_F"      |%"U16_F"%"U16_F"%"U16_F"|    %4"U16_F"   | (id, flags, offset)\n",
01062                     lwip_ntohs(IPH_ID(iphdr)),
01063                     (u16_t)(lwip_ntohs(IPH_OFFSET(iphdr)) >> 15 & 1),
01064                     (u16_t)(lwip_ntohs(IPH_OFFSET(iphdr)) >> 14 & 1),
01065                     (u16_t)(lwip_ntohs(IPH_OFFSET(iphdr)) >> 13 & 1),
01066                     (u16_t)(lwip_ntohs(IPH_OFFSET(iphdr)) & IP_OFFMASK)));
01067   LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
01068   LWIP_DEBUGF(IP_DEBUG, ("|  %3"U16_F"  |  %3"U16_F"  |    0x%04"X16_F"     | (ttl, proto, chksum)\n",
01069                     (u16_t)IPH_TTL(iphdr),
01070                     (u16_t)IPH_PROTO(iphdr),
01071                     lwip_ntohs(IPH_CHKSUM(iphdr))));
01072   LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
01073   LWIP_DEBUGF(IP_DEBUG, ("|  %3"U16_F"  |  %3"U16_F"  |  %3"U16_F"  |  %3"U16_F"  | (src)\n",
01074                     ip4_addr1_16(&iphdr->src),
01075                     ip4_addr2_16(&iphdr->src),
01076                     ip4_addr3_16(&iphdr->src),
01077                     ip4_addr4_16(&iphdr->src)));
01078   LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
01079   LWIP_DEBUGF(IP_DEBUG, ("|  %3"U16_F"  |  %3"U16_F"  |  %3"U16_F"  |  %3"U16_F"  | (dest)\n",
01080                     ip4_addr1_16(&iphdr->dest),
01081                     ip4_addr2_16(&iphdr->dest),
01082                     ip4_addr3_16(&iphdr->dest),
01083                     ip4_addr4_16(&iphdr->dest)));
01084   LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
01085 }
01086 #endif /* IP_DEBUG */
01087 
01088 #endif /* LWIP_IPV4 */