only broadcast MAC addr works for regular ARP requests. Refactor link_open
This commit is contained in:
mykola2312
parent
2be92f0ad6
commit
94ae687abf
1 changed files with 68 additions and 36 deletions
104
main.c
104
main.c
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@ -5,6 +5,7 @@
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#include <string.h>
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#include <unistd.h>
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#include <sys/types.h>
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#include <sys/param.h>
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#include <sys/ioctl.h>
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#include <sys/socket.h>
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#include <net/if.h>
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@ -12,6 +13,7 @@
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#include <net/ethernet.h>
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#include <linux/if_packet.h>
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#define FRAME_MIN_LEN 64
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#define MTU 1500
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void parse_mac(const char* str, uint8_t* mac) {
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@ -38,26 +40,19 @@ struct linkinterface {
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socklen_t if_len;
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uint8_t host[ETH_ALEN];
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uint8_t gateway[ETH_ALEN];
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int fd; // raw socket
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int if_idx;
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};
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struct linkinterface* link_parse(const char* if_name, const char* gateway) {
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struct linkinterface* link_open(const char* if_name) {
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struct linkinterface* link = (struct linkinterface*)malloc(sizeof(struct linkinterface));
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link->if_name = strdup(if_name);
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link->if_len = strlen(link->if_name);
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parse_mac(gateway, link->gateway);
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return link;
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}
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int link_open(struct linkinterface* link) {
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link->fd = socket(PF_PACKET, SOCK_RAW, htons(ETH_P_ALL));
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if (link->fd < 0) {
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return 1;
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goto _bad0;
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}
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setsockopt(link->fd, SOL_SOCKET, SO_BINDTODEVICE, link->if_name, link->if_len);
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@ -66,18 +61,24 @@ int link_open(struct linkinterface* link) {
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memset(&netlink, '\0', sizeof(netlink));
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strncpy(netlink.ifr_ifrn.ifrn_name, link->if_name, IFNAMSIZ-1);
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if (ioctl(link->fd, SIOCGIFINDEX, &netlink) < 0) {
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return 1;
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goto _bad1;
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}
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link->if_idx = netlink.ifr_ifru.ifru_ivalue; // index
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memset(&netlink, '\0', sizeof(netlink));
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strncpy(netlink.ifr_ifrn.ifrn_name, link->if_name, IFNAMSIZ-1);
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if (ioctl(link->fd, SIOCGIFHWADDR, &netlink) < 0) {
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return 1;
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goto _bad1;
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}
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memcpy(link->host, netlink.ifr_ifru.ifru_hwaddr.sa_data, ETH_ALEN); // MAC
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return 0;
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return link;
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_bad1:
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close(link->fd);
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_bad0:
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free(link->if_name);
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free(link);
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return NULL;
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}
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void link_free(struct linkinterface* link) {
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@ -86,24 +87,38 @@ void link_free(struct linkinterface* link) {
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free(link);
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}
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ssize_t link_send(struct linkinterface* link, uint16_t type, uint8_t* packet, size_t len) {
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struct ether_header* ether = (struct ether_header*)packet;
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ssize_t link_send(struct linkinterface* link, const uint8_t* dstAddr,
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uint16_t type, uint8_t* packet, size_t len)
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{
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// ETHER FRAME MUST NOT BE LESS THAN 64 (60)
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size_t frame_len = MAX(60, len + sizeof(struct ether_header));
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uint8_t* frame = (uint8_t*)malloc(frame_len);
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memset(frame, '\0', frame_len);
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struct ether_header* ether = (struct ether_header*)frame;
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memcpy(ether->ether_shost, link->host, ETH_ALEN);
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memcpy(ether->ether_dhost, link->gateway, ETH_ALEN);
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memcpy(ether->ether_dhost, dstAddr, ETH_ALEN);
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ether->ether_type = htons(type);
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// copy packet data
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memcpy(frame + sizeof(struct ether_header), packet, len);
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struct sockaddr_ll ll_addr = {0};
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ll_addr.sll_family = PF_PACKET;
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//ll_addr.sll_protocol = htons(type);
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ll_addr.sll_ifindex = link->if_idx;
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ll_addr.sll_halen = ETH_ALEN;
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memcpy(ll_addr.sll_addr, link->gateway, ETH_ALEN);
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memcpy(ll_addr.sll_addr, dstAddr, ETH_ALEN);
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return sendto(link->fd, packet, len, 0,
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size_t sent = sendto(link->fd, frame, frame_len, 0,
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(const struct sockaddr*)&ll_addr, sizeof(ll_addr));
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free(frame);
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return sent;
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}
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ssize_t link_recv(struct linkinterface* link, uint16_t type, uint8_t* packet, size_t len) {
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ssize_t link_recv(struct linkinterface* link, const uint8_t* srcAddr,
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uint16_t type, uint8_t* packet, size_t len)
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{
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char buffer[MTU];
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uint16_t want_type = htons(type);
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do {
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@ -112,9 +127,9 @@ ssize_t link_recv(struct linkinterface* link, uint16_t type, uint8_t* packet, si
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struct ether_header* ether = (struct ether_header*)buffer;
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// check received packet's source MAC
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// if its someone else than gateway - skip
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if (memcmp(ether->ether_shost, link->gateway, ETH_ALEN)) {
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continue; // not our gateway
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// if its someone else than source - skip
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if (memcmp(ether->ether_shost, srcAddr, ETH_ALEN)) {
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continue; // not our source
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}
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if (memcmp(ether->ether_dhost, link->host, ETH_ALEN)) {
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continue; // not our host
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@ -131,7 +146,7 @@ ssize_t link_recv(struct linkinterface* link, uint16_t type, uint8_t* packet, si
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// TODO: timeout
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}
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#define ARP_HW_ETHER 0x000F
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#define ARP_HW_ETHER 0x0001
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#define ARP_PT_IP 0x0800
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#define ARP_OP_REQUEST 1
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@ -142,8 +157,6 @@ ssize_t link_recv(struct linkinterface* link, uint16_t type, uint8_t* packet, si
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#define INART_OP_REPLY 9
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typedef struct arp_packet_s {
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struct ether_header ether;
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uint16_t hrd; // Hardware address space (e.g., Ethernet, Packet Radio Net.)
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uint16_t pro; // Protocol address space. For Ethernet hardware, this is from the set of type fields ether_typ$<protocol>.
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uint8_t hln; // byte length of each hardware address
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@ -157,32 +170,51 @@ typedef struct arp_packet_s {
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int main(int argc, char** argv) {
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// ifname hostMAC gatewayMAC targetMAC
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struct linkinterface* link = link_parse(argv[1], argv[2]);
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uint8_t target[ETH_ALEN];
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parse_mac(argv[3], target);
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if (link_open(link) < 0) {
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struct linkinterface* link = link_open(argv[1]);
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if (!link) {
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perror("link_open");
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return 1;
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}
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print_mac(link->host);
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uint8_t target[ETH_ALEN];
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parse_mac(argv[2], target);
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uint8_t ip[4] = {192, 168, 100, 3};
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// test arp send
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// test InARP send
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// arp_packet_t arp;
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// arp.hrd = htons(ARP_HW_ETHER);
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// arp.pro = htons(ARP_PT_IP);
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// arp.hln = ETH_ALEN;
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// arp.pln = 4;
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// arp.op = htons(INARP_OP_REQUEST);
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// memcpy(arp.sha, link->host, ETH_ALEN);
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// memcpy(arp.spa, ip, 4);
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// memcpy(arp.tha, target, ETH_ALEN);
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// memset(arp.tpa, '\0', 4);
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uint8_t targetIp[4] = {192, 168, 100, 4};
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arp_packet_t arp;
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arp.hrd = htons(ARP_HW_ETHER);
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arp.pro = htons(ARP_PT_IP);
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arp.hln = ETH_ALEN;
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arp.pln = 4;
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arp.op = htons(INARP_OP_REQUEST);
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arp.op = htons(ARP_OP_REQUEST);
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memcpy(arp.sha, link->host, ETH_ALEN);
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memcpy(arp.spa, ip, 4);
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memcpy(arp.tha, target, ETH_ALEN);
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memset(arp.tpa, '\0', 4);
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memset(arp.tha, '\0', ETH_ALEN);
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memcpy(arp.tpa, targetIp, 4);
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ssize_t sent = link_send(link, ETHERTYPE_ARP, (uint8_t*)&arp, sizeof(arp));
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const uint8_t broadcast[6] = {0xFF,0xFF,0xFF,0xFF,0xFF,0xFF};
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// ssize_t sent = link_send(link, ETHERTYPE_ARP, (uint8_t*)&arp, sizeof(arp));
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// printf("sent %ld\n", sent);
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// sent = link_send(link, target, ETHERTYPE_ARP, (uint8_t*)&arp, sizeof(arp));
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// printf("sent %ld\n", sent);
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ssize_t sent = link_send(link, broadcast, ETHERTYPE_ARP, (uint8_t*)&arp, sizeof(arp));
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printf("sent %ld\n", sent);
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link_free(link);
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