/**
* Outbound TTL/HOPL check.
*/
static int
pxudp_ttl_expired(struct pbuf *p)
{
int ttl;
if (ip_current_is_v6()) {
ttl = IP6H_HOPLIM(ip6_current_header());
}
else {
ttl = IPH_TTL(ip_current_header());
}
if (RT_UNLIKELY(ttl <= 1)) {
int status = pbuf_header(p, ip_current_header_tot_len() + UDP_HLEN);
if (RT_LIKELY(status == 0)) {
if (ip_current_is_v6()) {
icmp6_time_exceeded(p, ICMP6_TE_HL);
}
else {
icmp_time_exceeded(p, ICMP_TE_TTL);
}
}
pbuf_free(p);
return 1;
}
return 0;
}
/*
* Forward an IP packet. It finds an appropriate route for the packet,
* decrements the TTL value of the packet, adjusts the checksum and outputs
* the packet on the appropriate interface.
*/
static void
ip_forward (ip_t *ip, buf_t *p, ip_addr_const gateway, netif_t *netif,
ip_addr_const netif_ipaddr)
{
ip_hdr_t *iphdr = (ip_hdr_t*) p->payload;
/* Decrement TTL and send ICMP if ttl == 0. */
if (iphdr->ttl <= 1) {
/* Don't send ICMP messages in response to ICMP messages */
if (iphdr->proto != IP_PROTO_ICMP) {
icmp_time_exceeded (ip, p);
}
return;
}
iphdr->ttl--;
/* Incremental update of the IP checksum. */
if (iphdr->chksum_h != 0xff)
iphdr->chksum_h += 1;
else if (iphdr->chksum_l != 0xff) {
iphdr->chksum_h = 0;
iphdr->chksum_l += 1;
} else {
iphdr->chksum_h = 1;
iphdr->chksum_l = 0;
}
/* Forwarding packet to netif. */
if (! gateway)
gateway = iphdr->dest.var;
netif_output (netif, p, gateway, netif_ipaddr);
++ip->forw_datagrams;
}
/**
* Forwards an IP packet. It finds an appropriate route for the
* packet, decrements the TTL value of the packet, adjusts the
* checksum and outputs the packet on the appropriate interface.
*
* @param p the packet to forward (p->payload points to IP header)
* @param iphdr the IP header of the input packet
* @param inp the netif on which this packet was received
* @return the netif on which the packet was sent (NULL if it wasn't sent)
*/
static struct netif *
ip_forward(struct pbuf *p, struct ip_hdr *iphdr, struct netif *inp)
{
struct netif *netif;
PERF_START;
/* Find network interface where to forward this IP packet to. */
netif = ip_route((struct ip_addr *)&(iphdr->dest));
if (netif == NULL) {
LWIP_DEBUGF(IP_DEBUG, ("ip_forward: no forwarding route for 0x%"X32_F" found\n",
iphdr->dest.addr));
snmp_inc_ipoutnoroutes();
return (struct netif *)NULL;
}
/* Do not forward packets onto the same network interface on which
* they arrived. */
if (netif == inp) {
LWIP_DEBUGF(IP_DEBUG, ("ip_forward: not bouncing packets back on incoming interface.\n"));
snmp_inc_ipoutnoroutes();
return (struct netif *)NULL;
}
/* decrement TTL */
IPH_TTL_SET(iphdr, IPH_TTL(iphdr) - 1);
/* send ICMP if TTL == 0 */
if (IPH_TTL(iphdr) == 0) {
snmp_inc_ipinhdrerrors();
#if LWIP_ICMP
/* Don't send ICMP messages in response to ICMP messages */
if (IPH_PROTO(iphdr) != IP_PROTO_ICMP) {
icmp_time_exceeded(p, ICMP_TE_TTL);
}
#endif /* LWIP_ICMP */
return (struct netif *)NULL;
}
/* Incrementally update the IP checksum. */
if (IPH_CHKSUM(iphdr) >= htons(0xffff - 0x100)) {
IPH_CHKSUM_SET(iphdr, IPH_CHKSUM(iphdr) + htons(0x100) + 1);
} else {
IPH_CHKSUM_SET(iphdr, IPH_CHKSUM(iphdr) + htons(0x100));
}
LWIP_DEBUGF(IP_DEBUG, ("ip_forward: forwarding packet to 0x%"X32_F"\n",
iphdr->dest.addr));
IP_STATS_INC(ip.fw);
IP_STATS_INC(ip.xmit);
snmp_inc_ipforwdatagrams();
PERF_STOP("ip_forward");
/* transmit pbuf on chosen interface */
netif->output(netif, p, (struct ip_addr *)&(iphdr->dest));
return netif;
}
/**
* Free a datagram (struct ip_reassdata) and all its pbufs.
* Updates the total count of enqueued pbufs (ip_reass_pbufcount),
* SNMP counters and sends an ICMP time exceeded packet.
*
* @param ipr datagram to free
* @param prev the previous datagram in the linked list
* @return the number of pbufs freed
*/
static int
ip_reass_free_complete_datagram(struct ip_reassdata *ipr, struct ip_reassdata *prev)
{
u16_t pbufs_freed = 0;
u8_t clen;
struct pbuf *p;
struct ip_reass_helper *iprh;
LWIP_ASSERT("prev != ipr", prev != ipr);
if (prev != NULL) {
LWIP_ASSERT("prev->next == ipr", prev->next == ipr);
}
snmp_inc_ipreasmfails();
#if LWIP_ICMP
iprh = (struct ip_reass_helper *)ipr->p->payload;
if (iprh->start == 0) {
/* The first fragment was received, send ICMP time exceeded. */
/* First, de-queue the first pbuf from r->p. */
p = ipr->p;
ipr->p = iprh->next_pbuf;
/* Then, copy the original header into it. */
SMEMCPY(p->payload, &ipr->iphdr, IP_HLEN);
icmp_time_exceeded(p, ICMP_TE_FRAG);
clen = pbuf_clen(p);
LWIP_ASSERT("pbufs_freed + clen <= 0xffff", pbufs_freed + clen <= 0xffff);
pbufs_freed += clen;
pbuf_free(p);
}
#endif /* LWIP_ICMP */
/* First, free all received pbufs. The individual pbufs need to be released
separately as they have not yet been chained */
p = ipr->p;
while (p != NULL) {
struct pbuf *pcur;
iprh = (struct ip_reass_helper *)p->payload;
pcur = p;
/* get the next pointer before freeing */
p = iprh->next_pbuf;
clen = pbuf_clen(pcur);
LWIP_ASSERT("pbufs_freed + clen <= 0xffff", pbufs_freed + clen <= 0xffff);
pbufs_freed += clen;
pbuf_free(pcur);
}
/* Then, unchain the struct ip_reassdata from the list and free it. */
ip_reass_dequeue_datagram(ipr, prev);
LWIP_ASSERT("ip_reass_pbufcount >= clen", ip_reass_pbufcount >= pbufs_freed);
ip_reass_pbufcount -= pbufs_freed;
return pbufs_freed;
}
/*-----------------------------------------------------------------------------------*/
static void
ip_forward(struct pbuf *p, struct ip_hdr *iphdr, struct netif *inp)
{
static struct netif *netif;
PERF_START;
if((netif = ip_route((struct ip_addr *)&(iphdr->dest))) == NULL) {
DEBUGF(IP_DEBUG, ("ip_forward: no forwarding route for 0x%lx found\n",
iphdr->dest.addr));
return;
}
/* Don't forward packets onto the same network interface on which
they arrived. */
if(netif == inp) {
DEBUGF(IP_DEBUG, ("ip_forward: not forward packets back on incoming interface.\n"));
return;
}
/* Decrement TTL and send ICMP if ttl == 0. */
IPH_TTL_SET(iphdr, IPH_TTL(iphdr) - 1);
if(IPH_TTL(iphdr) == 0) {
/* Don't send ICMP messages in response to ICMP messages */
if(IPH_PROTO(iphdr) != IP_PROTO_ICMP) {
icmp_time_exceeded(p, ICMP_TE_TTL);
}
return;
}
/* Incremental update of the IP checksum. */
if(IPH_CHKSUM(iphdr) >= htons(0xffff - 0x100)) {
IPH_CHKSUM_SET(iphdr, IPH_CHKSUM(iphdr) + htons(0x100) + 1);
} else {
IPH_CHKSUM_SET(iphdr, IPH_CHKSUM(iphdr) + htons(0x100));
}
DEBUGF(IP_DEBUG, ("ip_forward: forwarding packet to 0x%lx\n",
iphdr->dest.addr));
#ifdef IP_STATS
++stats.ip.fw;
++stats.ip.xmit;
#endif /* IP_STATS */
PERF_STOP("ip_forward");
netif->output(netif, p, (struct ip_addr *)&(iphdr->dest));
}
static void
ip_forward(struct pbuf *p, struct ip_hdr *iphdr)
{
struct netif *netif;
PERF_START;
if ((netif = ip_route((struct ip_addr *)&(iphdr->dest))) == NULL) {
LWIP_DEBUGF(IP_DEBUG, ("ip_input: no forwarding route found for "));
#if IP_DEBUG
ip_addr_debug_print(IP_DEBUG, ((struct ip_addr *)&(iphdr->dest)));
#endif /* IP_DEBUG */
LWIP_DEBUGF(IP_DEBUG, ("\n"));
pbuf_free(p);
return;
}
/* Decrement TTL and send ICMP if ttl == 0. */
if (--iphdr->hoplim == 0) {
#if LWIP_ICMP
/* Don't send ICMP messages in response to ICMP messages */
if (iphdr->nexthdr != IP_PROTO_ICMP) {
icmp_time_exceeded(p, ICMP_TE_TTL);
}
#endif /* LWIP_ICMP */
pbuf_free(p);
return;
}
/* Incremental update of the IP checksum. */
/* if (iphdr->chksum >= htons(0xffff - 0x100)) {
iphdr->chksum += htons(0x100) + 1;
} else {
iphdr->chksum += htons(0x100);
}*/
LWIP_DEBUGF(IP_DEBUG, ("ip_forward: forwarding packet to "));
#if IP_DEBUG
ip_addr_debug_print(IP_DEBUG, ((struct ip_addr *)&(iphdr->dest)));
#endif /* IP_DEBUG */
LWIP_DEBUGF(IP_DEBUG, ("\n"));
IP_STATS_INC(ip.fw);
IP_STATS_INC(ip.xmit);
PERF_STOP("ip_forward");
netif->output(netif, p, (struct ip_addr *)&(iphdr->dest));
}
/**
* ICMP Echo Request in pbuf "p" is to be proxied.
*/
static void
pxping_recv4(void *arg, struct pbuf *p)
{
struct pxping *pxping = (struct pxping *)arg;
const struct ip_hdr *iph;
const struct icmp_echo_hdr *icmph;
u16_t iphlen;
size_t bufsize;
struct pong4 *pong;
IPAddr dst;
int mapped;
int ttl;
IP_OPTION_INFORMATION opts;
void *reqdata;
size_t reqsize;
int status;
pong = NULL;
iphlen = ip_current_header_tot_len();
if (RT_UNLIKELY(iphlen != IP_HLEN)) { /* we don't do options */
goto out;
}
iph = (const struct ip_hdr *)ip_current_header();
icmph = (const struct icmp_echo_hdr *)p->payload;
mapped = pxremap_outbound_ip4((ip_addr_t *)&dst, (ip_addr_t *)&iph->dest);
if (RT_UNLIKELY(mapped == PXREMAP_FAILED)) {
goto out;
}
ttl = IPH_TTL(iph);
if (mapped == PXREMAP_ASIS) {
if (RT_UNLIKELY(ttl == 1)) {
status = pbuf_header(p, iphlen); /* back to IP header */
if (RT_LIKELY(status == 0)) {
icmp_time_exceeded(p, ICMP_TE_TTL);
}
goto out;
}
--ttl;
}
status = pbuf_header(p, -(u16_t)sizeof(*icmph)); /* to ping payload */
if (RT_UNLIKELY(status != 0)) {
goto out;
}
bufsize = sizeof(ICMP_ECHO_REPLY) + p->tot_len;
pong = (struct pong4 *)malloc(sizeof(*pong) - sizeof(pong->buf) + bufsize);
if (RT_UNLIKELY(pong == NULL)) {
goto out;
}
pong->bufsize = bufsize;
pong->netif = pxping->netif;
memcpy(&pong->reqiph, iph, sizeof(*iph));
memcpy(&pong->reqicmph, icmph, sizeof(*icmph));
reqsize = p->tot_len;
if (p->next == NULL) {
/* single pbuf can be directly used as request data source */
reqdata = p->payload;
}
else {
/* data from pbuf chain must be concatenated */
pbuf_copy_partial(p, pong->buf, p->tot_len, 0);
reqdata = pong->buf;
}
opts.Ttl = ttl;
opts.Tos = IPH_TOS(iph); /* affected by DisableUserTOSSetting key */
opts.Flags = (IPH_OFFSET(iph) & PP_HTONS(IP_DF)) != 0 ? IP_FLAG_DF : 0;
opts.OptionsSize = 0;
opts.OptionsData = 0;
status = IcmpSendEcho2(pxping->hdl4, NULL,
pxping->callback4, pong,
dst, reqdata, (WORD)reqsize, &opts,
pong->buf, (DWORD)pong->bufsize,
5 * 1000 /* ms */);
if (RT_UNLIKELY(status != 0)) {
DPRINTF(("IcmpSendEcho2: unexpected status %d\n", status));
goto out;
}
else if ((status = GetLastError()) != ERROR_IO_PENDING) {
int code;
DPRINTF(("IcmpSendEcho2: error %d\n", status));
switch (status) {
case ERROR_NETWORK_UNREACHABLE:
code = ICMP_DUR_NET;
break;
case ERROR_HOST_UNREACHABLE:
code = ICMP_DUR_HOST;
break;
default:
code = -1;
break;
}
if (code != -1) {
/* move payload back to IP header */
status = pbuf_header(p, (u16_t)(sizeof(*icmph) + iphlen));
if (RT_LIKELY(status == 0)) {
icmp_dest_unreach(p, code);
}
}
goto out;
}
pong = NULL; /* callback owns it now */
out:
if (pong != NULL) {
free(pong);
}
pbuf_free(p);
}
