void
icmp_dest_unreach(struct pbuf *p, enum icmp_dur_type t)
{
struct pbuf *q;
struct ip_hdr *iphdr;
struct icmp_dur_hdr *idur;
q = pbuf_alloc(PBUF_IP, 8 + IP_HLEN + 8, PBUF_RAM);
/* ICMP header + IP header + 8 bytes of data */
iphdr = p->payload;
idur = q->payload;
ICMPH_TYPE_SET(idur, ICMP_DUR);
ICMPH_CODE_SET(idur, t);
memcpy((u8_t *)q->payload + 8, p->payload, IP_HLEN + 8);
/* calculate checksum */
idur->chksum = 0;
idur->chksum = inet_chksum(idur, q->len);
ICMP_STATS_INC(icmp.xmit);
/* increase number of messages attempted to send */
snmp_inc_icmpoutmsgs();
/* increase number of destination unreachable messages attempted to send */
snmp_inc_icmpoutdestunreachs();
ip_output(q, NULL, &(iphdr->src),
ICMP_TTL, 0, IP_PROTO_ICMP);
pbuf_free(q);
}
/**
* Send an icmp 'destination unreachable' packet, called from ip_input() if
* the transport layer protocol is unknown and from udp_input() if the local
* port is not bound.
*
* @param p the input packet for which the 'unreachable' should be sent,
* p->payload pointing to the IP header
* @param t type of the 'unreachable' packet
*/
void
icmp_dest_unreach(struct pbuf *p, enum icmp_dur_type t)
{
struct pbuf *q;
struct ip_hdr *iphdr;
struct icmp_dur_hdr *idur;
/* ICMP header + IP header + 8 bytes of data */
q = pbuf_alloc(PBUF_IP, sizeof(struct icmp_dur_hdr) + IP_HLEN + ICMP_DEST_UNREACH_DATASIZE,
PBUF_RAM);
if (q == NULL) {
LWIP_DEBUGF(ICMP_DEBUG, ("icmp_dest_unreach: failed to allocate pbuf for ICMP packet.\n"));
return;
}
LWIP_ASSERT("check that first pbuf can hold icmp message",
(q->len >= (sizeof(struct icmp_dur_hdr) + IP_HLEN + ICMP_DEST_UNREACH_DATASIZE)));
iphdr = p->payload;
idur = q->payload;
ICMPH_TYPE_SET(idur, ICMP_DUR);
ICMPH_CODE_SET(idur, t);
SMEMCPY((u8_t *)q->payload + sizeof(struct icmp_dur_hdr), p->payload,
IP_HLEN + ICMP_DEST_UNREACH_DATASIZE);
/* calculate checksum */
idur->chksum = 0;
idur->chksum = inet_chksum(idur, q->len);
ICMP_STATS_INC(icmp.xmit);
/* increase number of messages attempted to send */
snmp_inc_icmpoutmsgs();
/* increase number of destination unreachable messages attempted to send */
snmp_inc_icmpoutdestunreachs();
ip_output(q, NULL, &(iphdr->src), ICMP_TTL, 0, IP_PROTO_ICMP);
pbuf_free(q);
}