2

linux_chat.c

@@ -4,9 +4,42 @@
 #include <arpa/inet.h>
 #include <sys/socket.h>
 #include <sys/select.h>
+#include <pthread.h>
 
 #include "common.h"
 
+typedef struct {
+    int sock;
+    uint8_t *recv_seq;
+    struct sockaddr_in6 *peer;
+} recv_args;
+
+void *receiver(void *arg) {
+    recv_args *a = (recv_args *)arg;
+    while (1) {
+        fd_set fds;
+        FD_ZERO(&fds);
+        FD_SET(a->sock, &fds);
+        struct timeval tv = {0, 100000};
+
+        if (select(a->sock + 1, &fds, NULL, NULL, &tv) > 0) {
+            struct packet rcv;
+            recvfrom(a->sock, &rcv, sizeof(rcv), 0, NULL, NULL);
+            rcv.payload[sizeof(rcv.payload) - 1] = '\0';
+            if (rcv.type == TYPE_DATA) {
+                if (rcv.seq == *a->recv_seq) {
+                    printf("\npeer: %s\n", rcv.payload);
+                    *a->recv_seq ^= 1;
+                }
+                rcv.type = TYPE_ACK;
+                sendto(a->sock, &rcv, 2, 0,
+                       (struct sockaddr *)a->peer, sizeof(*a->peer));
+            }
+        }
+    }
+    return NULL;
+}
+
 /* 停等协议发送（带超时重传） */
 void send_with_stopwait(int sock,
                         struct sockaddr_in6 *peer,
@@ -60,39 +93,25 @@ int main(int argc, char *argv[])
     memset(&peer, 0, sizeof(peer));
     peer.sin6_family = AF_INET6;
     peer.sin6_port = htons(PORT);
-    inet_pton(AF_INET6, argv[1], &peer.sin6_addr);
+    if (inet_pton(AF_INET6, argv[1], &peer.sin6_addr) != 1) {
+        printf("无效的 IPv6 地址\n");
+        return 1;
+    }
 
     uint8_t send_seq = 0;
     uint8_t recv_seq = 0;
-    struct packet pkt, rcv;
+    struct packet pkt;
 
     memset(&pkt, 0, sizeof(pkt));
-    memset(&rcv, 0, sizeof(rcv));
 
     printf("Linux UDP IPv6 Stop-Wait Chat\n");
 
+    // 启动接收线程
+    recv_args args = {sock, &recv_seq, &peer};
+    pthread_t recv_thread;
+    pthread_create(&recv_thread, NULL, receiver, &args);
+
     while (1) {
-        /* 非阻塞接收 */
-        fd_set fds;
-        FD_ZERO(&fds);
-        FD_SET(sock, &fds);
-        struct timeval tv = {0, 100000};
-
-        if (select(sock + 1, &fds, NULL, NULL, &tv) > 0) {
-            recvfrom(sock, &rcv, sizeof(rcv), 0, NULL, NULL);
-            rcv.payload[sizeof(rcv.payload) - 1] = '\0';
-            if (rcv.type == TYPE_DATA) {
-                if (rcv.seq == recv_seq) {
-                    printf("\npeer: %s\n", rcv.payload);
-                    recv_seq ^= 1;
-                }
-                rcv.type = TYPE_ACK;
-                sendto(sock, &rcv, 2, 0,
-                       (struct sockaddr *)&peer, sizeof(peer));
-            }
-        }
-
-        /* 发送 */
         printf(">> ");
         if (!fgets(pkt.payload, sizeof(pkt.payload), stdin))
             break;

windows_chat.c

@@ -2,11 +2,43 @@
 #include <string.h>
 #include <winsock2.h>
 #include <ws2tcpip.h>
+#include <process.h>
 
 #include "common.h"
 
 #pragma comment(lib, "ws2_32.lib")
 
+typedef struct {
+    SOCKET sock;
+    uint8_t *recv_seq;
+    struct sockaddr_in6 *peer;
+} recv_args;
+
+void receiver(void *arg) {
+    recv_args *a = (recv_args *)arg;
+    while (1) {
+        fd_set fds;
+        FD_ZERO(&fds);
+        FD_SET(a->sock, &fds);
+        TIMEVAL tv = {0, 100000};
+
+        if (select(a->sock + 1, &fds, NULL, NULL, &tv) > 0) {
+            struct packet rcv;
+            recvfrom(a->sock, (char *)&rcv, sizeof(rcv), 0, NULL, NULL);
+            rcv.payload[sizeof(rcv.payload) - 1] = '\0';
+            if (rcv.type == TYPE_DATA) {
+                if (rcv.seq == *a->recv_seq) {
+                    printf("\npeer: %s\n", rcv.payload);
+                    *a->recv_seq ^= 1;
+                }
+                rcv.type = TYPE_ACK;
+                sendto(a->sock, (char *)&rcv, 2, 0,
+                       (struct sockaddr *)a->peer, sizeof(*a->peer));
+            }
+        }
+    }
+}
+
 void send_with_stopwait(SOCKET sock,
                         struct sockaddr_in6 *peer,
                         struct packet *pkt, int pkt_len)
@@ -14,6 +46,7 @@ void send_with_stopwait(SOCKET sock,
     int addr_len = sizeof(*peer);
 
     while (1) {
+        printf("Sending seq %d\n", pkt->seq);
         sendto(sock, (char *)pkt, pkt_len, 0,
                (struct sockaddr *)peer, addr_len);
 
@@ -26,10 +59,13 @@ void send_with_stopwait(SOCKET sock,
         tv.tv_usec = 0;
 
         int ret = select(sock + 1, &fds, NULL, NULL, &tv);
+        printf("Select returned %d\n", ret);
         if (ret > 0) {
             struct packet ack;
             recvfrom(sock, (char *)&ack, sizeof(ack), 0, NULL, NULL);
+            printf("Received ack seq %d type %d\n", ack.seq, ack.type);
             if (ack.type == TYPE_ACK && ack.seq == pkt->seq) {
+                printf("Correct ACK received\n");
                 return;
             }
         }
@@ -58,37 +94,24 @@ int main(int argc, char *argv[])
     struct sockaddr_in6 peer = {0};
     peer.sin6_family = AF_INET6;
     peer.sin6_port = htons(PORT);
-    inet_pton(AF_INET6, argv[1], &peer.sin6_addr);
+    if (inet_pton(AF_INET6, argv[1], &peer.sin6_addr) != 1) {
+        printf("无效的 IPv6 地址\n");
+        return 1;
+    }
 
     uint8_t send_seq = 0;
     uint8_t recv_seq = 0;
-    struct packet pkt, rcv;
+    struct packet pkt;
 
     memset(&pkt, 0, sizeof(pkt));
-    memset(&rcv, 0, sizeof(rcv));
 
     printf("Windows UDP IPv6 Stop-Wait Chat\n");
 
+    // 启动接收线程
+    recv_args args = {sock, &recv_seq, &peer};
+    _beginthread(receiver, 0, &args);
+
     while (1) {
-        fd_set fds;
-        FD_ZERO(&fds);
-        FD_SET(sock, &fds);
-        TIMEVAL tv = {0, 100000};
-
-        if (select(sock + 1, &fds, NULL, NULL, &tv) > 0) {
-            recvfrom(sock, (char *)&rcv, sizeof(rcv), 0, NULL, NULL);
-            rcv.payload[sizeof(rcv.payload) - 1] = '\0';
-            if (rcv.type == TYPE_DATA) {
-                if (rcv.seq == recv_seq) {
-                    printf("\npeer: %s\n", rcv.payload);
-                    recv_seq ^= 1;
-                }
-                rcv.type = TYPE_ACK;
-                sendto(sock, (char *)&rcv, 2, 0,
-                       (struct sockaddr *)&peer, sizeof(peer));
-            }
-        }
-
         printf(">> ");
         if (!fgets(pkt.payload, sizeof(pkt.payload), stdin))
             break;