static int icmp_send(uint8_t type, uint8_t code, const void *body,
size_t body_sz, struct sk_buff *skb) {
int ret;
size_t size;
if (ip_out_ops == NULL) {
skb_free(skb);
return -ENOSYS; /* error: not implemented */
}
size = sizeof *icmp_hdr(skb) + body_sz;
assert(ip_out_ops->make_pack != NULL);
ret = ip_out_ops->make_pack(NULL, NULL, &size, &skb);
if (ret != 0) {
skb_free(skb);
return ret; /* error: see ret */
}
else if (size != sizeof *icmp_hdr(skb) + body_sz) {
skb_free(skb);
return -EMSGSIZE; /* error: message is too big */
}
icmp_build(icmp_hdr(skb), type, code, body, body_sz);
icmp_set_check_field(icmp_hdr(skb), ip_hdr(skb));
assert(ip_out_ops->snd_pack != NULL);
return ip_out_ops->snd_pack(skb);
}
static int icmp_rcv(struct sk_buff *skb) {
struct icmphdr *icmph;
uint16_t old_check;
log_debug("%p len %zu", skb, skb->len);
if (sizeof *icmph > ip_data_length(ip_hdr(skb))) {
log_error("invalid length (%zu > %zu)",
sizeof *icmph, ip_data_length(ip_hdr(skb)));
skb_free(skb);
return 0; /* error: invalid length */
}
if (NULL == skb_declone(skb)) {
log_error("can't declone data");
skb_free(skb);
return -ENOMEM; /* error: can't declone data */
}
icmph = icmp_hdr(skb);
assert(icmph != NULL);
old_check = icmph->check;
icmp_set_check_field(icmph, ip_hdr(skb));
if (old_check != icmph->check) {
log_error("bad checksum");
skb_free(skb);
return 0; /* error: bad checksum */
}
switch (icmph->type) {
default:
log_error("icmp_rcv: unknown type: %hhu\n", icmph->type);
break; /* error: unknown type */
case ICMP_ECHO_REPLY:
case ICMP_TIMESTAMP_REPLY:
case ICMP_INFO_REPLY:
break;
case ICMP_DEST_UNREACH:
return icmp_hnd_dest_unreach(icmph, &icmph->body[0].dest_unreach, skb);
case ICMP_SOURCE_QUENCH:
return icmp_hnd_source_quench(icmph,
&icmph->body[0].source_quench, skb);
case ICMP_REDIRECT:
case ICMP_TIME_EXCEED:
case ICMP_INFO_REQUEST:
break; /* error: not implemented */
case ICMP_ECHO_REQUEST:
return icmp_hnd_echo_request(icmph, &icmph->body[0].echo, skb);
case ICMP_PARAM_PROB:
return icmp_hnd_param_prob(icmph, &icmph->body[0].param_prob, skb);
case ICMP_TIMESTAMP_REQUEST:
return icmp_hnd_timestamp_request(icmph,
&icmph->body[0].timestamp, skb);
}
skb_free(skb);
return 0;
}
