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#include "proto.h"
#include "util.h"
enum {
Type = 0,
Code = 1,
Checksum = 2,
Payload = 4,
};
void icmp_parse(const uint8_t *buf, size_t len, struct ipv4 ip) {
if (len < Payload) return;
uint8_t type = buf[Type];
if (type == 8 && ip.dst == state.ip) {
/* echo reply */
icmp_send(buf + Payload, len - Payload, (struct icmp){
.type = 0,
.ip.dst = ip.src,
.ip.e.dst = ip.e.src,
});
}
}
void icmp_send(const void *payload, size_t len, struct icmp i) {
i.ip.proto = 1;
uint8_t *pkt = malloc(Payload + len);
pkt[Type] = i.type;
pkt[Code] = i.code;
memcpy(pkt + Payload, payload, len);
nput16(pkt + Checksum, 0);
nput16(pkt + Checksum, ip_checksum(pkt, Payload + len));
ipv4_send(pkt, Payload + len, i.ip);
free(pkt);
}
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