diff options
Diffstat (limited to 'lwip/src/core/ipv4/icmp.c')
| -rw-r--r-- | lwip/src/core/ipv4/icmp.c | 18 |
1 files changed, 12 insertions, 6 deletions
diff --git a/lwip/src/core/ipv4/icmp.c b/lwip/src/core/ipv4/icmp.c index a462ccd..59b493a 100644 --- a/lwip/src/core/ipv4/icmp.c +++ b/lwip/src/core/ipv4/icmp.c @@ -62,7 +62,7 @@ #define LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN 1 #endif /* LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN */ -/* The amount of data from the original packet to return in a dest-unreachable */ +/* The maximum amount of data from the original packet to return in a dest-unreachable */ #define ICMP_DEST_UNREACH_DATASIZE 8 static void icmp_send_response(struct pbuf *p, u8_t type, u8_t code); @@ -345,20 +345,26 @@ icmp_send_response(struct pbuf *p, u8_t type, u8_t code) struct icmp_echo_hdr *icmphdr; ip4_addr_t iphdr_src; struct netif *netif; + u16_t response_pkt_len; /* increase number of messages attempted to send */ MIB2_STATS_INC(mib2.icmpoutmsgs); - /* ICMP header + IP header + 8 bytes of data */ - q = pbuf_alloc(PBUF_IP, sizeof(struct icmp_echo_hdr) + IP_HLEN + ICMP_DEST_UNREACH_DATASIZE, - PBUF_RAM); + /* Keep IP header + up to 8 bytes */ + response_pkt_len = IP_HLEN + ICMP_DEST_UNREACH_DATASIZE; + if (p->tot_len < response_pkt_len) { + response_pkt_len = p->tot_len; + } + + /* ICMP header + part of original packet */ + q = pbuf_alloc(PBUF_IP, sizeof(struct icmp_echo_hdr) + response_pkt_len, PBUF_RAM); if (q == NULL) { LWIP_DEBUGF(ICMP_DEBUG, ("icmp_time_exceeded: failed to allocate pbuf for ICMP packet.\n")); MIB2_STATS_INC(mib2.icmpouterrors); return; } LWIP_ASSERT("check that first pbuf can hold icmp message", - (q->len >= (sizeof(struct icmp_echo_hdr) + IP_HLEN + ICMP_DEST_UNREACH_DATASIZE))); + (q->len >= (sizeof(struct icmp_echo_hdr) + response_pkt_len))); iphdr = (struct ip_hdr *)p->payload; LWIP_DEBUGF(ICMP_DEBUG, ("icmp_time_exceeded from ")); @@ -375,7 +381,7 @@ icmp_send_response(struct pbuf *p, u8_t type, u8_t code) /* copy fields from original packet */ SMEMCPY((u8_t *)q->payload + sizeof(struct icmp_echo_hdr), (u8_t *)p->payload, - IP_HLEN + ICMP_DEST_UNREACH_DATASIZE); + response_pkt_len); ip4_addr_copy(iphdr_src, iphdr->src); #ifdef LWIP_HOOK_IP4_ROUTE_SRC |