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udp_input() operated by removing the IP and UDP headers, putting back

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the UDP header, then re-removing it.  However, pbuf_header() can't add
back the UDP header on pbufs of type PBUF_REF, so these would all get
dropped for bad checksum.  This change addresses the problem and
simplifies things by stripping each header just once.
This commit is contained in:
curtmcd 2006-05-26 02:40:54 +00:00
parent 047e3455f7
commit 6158aa684b
1 changed files with 5 additions and 4 deletions
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9
src/core/udp.c
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@ -98,7 +98,7 @@ udp_input(struct pbuf *p, struct netif *inp)
iphdr = p->payload; iphdr = p->payload;
if (pbuf_header(p, -((s16_t)(UDP_HLEN + IPH_HL(iphdr) * 4)))) { if (p->tot_len < (IPH_HL(iphdr) * 4 + UDP_HLEN)) {
/* drop short packets */ /* drop short packets */
LWIP_DEBUGF(UDP_DEBUG, LWIP_DEBUGF(UDP_DEBUG,
("udp_input: short UDP datagram (%"U16_F" bytes) discarded\n", p->tot_len)); ("udp_input: short UDP datagram (%"U16_F" bytes) discarded\n", p->tot_len));
@ -109,7 +109,9 @@ udp_input(struct pbuf *p, struct netif *inp)
goto end; goto end;
} }
udphdr = (struct udp_hdr *)((u8_t *)p->payload - UDP_HLEN); pbuf_header(p, -(s16_t)(IPH_HL(iphdr) * 4));
udphdr = (struct udp_hdr *)p->payload;
LWIP_DEBUGF(UDP_DEBUG, ("udp_input: received datagram of length %"U16_F"\n", p->tot_len)); LWIP_DEBUGF(UDP_DEBUG, ("udp_input: received datagram of length %"U16_F"\n", p->tot_len));
@ -168,7 +170,6 @@ udp_input(struct pbuf *p, struct netif *inp)
/* Check checksum if this is a match or if it was directed at us. */ /* Check checksum if this is a match or if it was directed at us. */
if (pcb != NULL || ip_addr_cmp(&inp->ip_addr, &iphdr->dest)) { if (pcb != NULL || ip_addr_cmp(&inp->ip_addr, &iphdr->dest)) {
LWIP_DEBUGF(UDP_DEBUG | DBG_TRACE, ("udp_input: calculating checksum\n")); LWIP_DEBUGF(UDP_DEBUG | DBG_TRACE, ("udp_input: calculating checksum\n"));
pbuf_header(p, UDP_HLEN);
#ifdef IPv6 #ifdef IPv6
if (iphdr->nexthdr == IP_PROTO_UDPLITE) { if (iphdr->nexthdr == IP_PROTO_UDPLITE) {
#else #else
@ -220,7 +221,7 @@ udp_input(struct pbuf *p, struct netif *inp)
if (!ip_addr_isbroadcast(&iphdr->dest, inp) && if (!ip_addr_isbroadcast(&iphdr->dest, inp) &&
!ip_addr_ismulticast(&iphdr->dest)) { !ip_addr_ismulticast(&iphdr->dest)) {
/* adjust pbuf pointer */ /* restore pbuf pointer */
p->payload = iphdr; p->payload = iphdr;
icmp_dest_unreach(p, ICMP_DUR_PORT); icmp_dest_unreach(p, ICMP_DUR_PORT);
} }