95 lines
2.6 KiB
C
95 lines
2.6 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <arpa/inet.h>
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#include <sys/socket.h>
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#include <sys/time.h>
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#include "common.h"
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#define LOCAL_PORT 9000
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#define PEER_PORT 9001
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#define TIMEOUT_MS 200
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int main(int argc, char *argv[]) {
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if (argc != 2) {
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printf("Usage: %s <Windows IPv6>\n", argv[0]);
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return 1;
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}
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int sock = socket(AF_INET6, SOCK_DGRAM, 0);
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struct sockaddr_in6 local = {0};
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local.sin6_family = AF_INET6;
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local.sin6_port = htons(LOCAL_PORT);
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local.sin6_addr = in6addr_any;
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bind(sock, (struct sockaddr*)&local, sizeof(local));
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struct sockaddr_in6 peer = {0};
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peer.sin6_family = AF_INET6;
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peer.sin6_port = htons(PEER_PORT);
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inet_pton(AF_INET6, argv[1], &peer.sin6_addr);
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struct timeval tv = {0, TIMEOUT_MS * 1000};
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setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv));
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uint8_t send_seq = 0;
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uint8_t waiting_ack = 0;
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packet_t last_pkt;
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while (1) {
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/* 尝试接收 */
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packet_t pkt;
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struct sockaddr_in6 from;
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socklen_t fromlen = sizeof(from);
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int n = recvfrom(sock, &pkt, sizeof(pkt), 0,
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(struct sockaddr*)&from, &fromlen);
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if (n > 0) {
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if (pkt.type == TYPE_DATA) {
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printf("\nPeer: %s", pkt.data);
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packet_t ack = {0};
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ack.type = TYPE_ACK;
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ack.seq = pkt.seq;
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sendto(sock, &ack, sizeof(ack), 0,
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(struct sockaddr*)&peer, sizeof(peer));
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}
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else if (pkt.type == TYPE_ACK &&
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waiting_ack && pkt.seq == send_seq) {
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waiting_ack = 0;
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send_seq ^= 1;
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}
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}
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/* 如果不在等 ACK，则允许发送 */
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if (!waiting_ack) {
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char buf[DATA_LEN];
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printf("You: ");
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fflush(stdout);
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if (fgets(buf, sizeof(buf), stdin) == NULL)
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continue;
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memset(&last_pkt, 0, sizeof(last_pkt));
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last_pkt.type = TYPE_DATA;
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last_pkt.seq = send_seq;
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last_pkt.length = strlen(buf);
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memcpy(last_pkt.data, buf, last_pkt.length);
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sendto(sock, &last_pkt, sizeof(last_pkt), 0,
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(struct sockaddr*)&peer, sizeof(peer));
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waiting_ack = 1;
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} else {
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/* 超时重传 */
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sendto(sock, &last_pkt, sizeof(last_pkt), 0,
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(struct sockaddr*)&peer, sizeof(peer));
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usleep(TIMEOUT_MS * 1000);
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}
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}
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}
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