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also get IP address of interface

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mykola2312 2024-12-19 17:48:23 +02:00
parent eba00ad9b2
commit ae8863ccc5
1 changed files with 16 additions and 4 deletions
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20
main.c
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@ -43,6 +43,7 @@ struct linkinterface {
socklen_t if_len;
uint8_t host[ETH_ALEN];
uint8_t host_ip[4];
int fd; // raw socket
int if_idx;
@ -91,6 +92,14 @@ struct linkinterface* link_open(const char* if_name) {
goto _bad1;
}
memcpy(link->host, netlink.ifr_ifru.ifru_hwaddr.sa_data, ETH_ALEN); // MAC
// get interface IP address
memset(&netlink, '\0', sizeof(netlink));
strncpy(netlink.ifr_ifrn.ifrn_name, link->if_name, IFNAMSIZ-1);
netlink.ifr_ifru.ifru_addr.sa_family = PF_INET;
if (ioctl(link->fd, SIOCGIFADDR, &netlink) < 0) {
goto _bad1;
}
memcpy(link->host_ip, &((struct sockaddr_in*)&netlink.ifr_ifru.ifru_addr)->sin_addr, 4);
return link;
_bad1:
@ -134,7 +143,7 @@ ssize_t link_send(struct linkinterface* link, const uint8_t* dstAddr,
return sent;
}
ssize_t link_recv(struct linkinterface* link, const uint8_t* srcAddr,
size_t link_recv(struct linkinterface* link, const uint8_t* srcAddr,
uint16_t type, frame_t frame, size_t len)
{
uint16_t want_type = htons(type);
@ -155,7 +164,12 @@ ssize_t link_recv(struct linkinterface* link, const uint8_t* srcAddr,
continue; // not wanted type
}
return rd;
// shift back ether header and realloc
size_t datalen = rd - sizeof(struct ether_header);
memmove(frame, (const uint8_t*)frame + sizeof(struct ether_header), datalen);
frame = realloc(frame, datalen);
return datalen;
} while (1);
// TODO: timeout
@ -196,8 +210,6 @@ int main(int argc, char** argv) {
// calculate checksum
icmp.checksum = htons(checksum((const uint8_t*)&icmp, sizeof(icmp)));
printf("%lu\n", sizeof(struct ip));
// IPv4 local broadcast
uint8_t ip_broadcast[4] = {255, 255, 255, 255};