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); }