更新 windows_chat.c

windows_chat.c

@@ -2,96 +2,101 @@
 #include <string.h>
 #include <winsock2.h>
 #include <ws2tcpip.h>
-#include <windows.h>
-
-#pragma comment(lib, "ws2_32.lib")
 
 #include "common.h"
 
-#define LOCAL_PORT 9001
+#pragma comment(lib, "ws2_32.lib")
-#define PEER_PORT  9000
-#define TIMEOUT_MS 200
 
-int main(int argc, char *argv[]) {
+void send_with_stopwait(SOCKET sock,
+                        struct sockaddr_in6 *peer,
+                        struct packet *pkt)
+{
+    int len = sizeof(*peer);
+
+    while (1) {
+        sendto(sock, (char *)pkt, sizeof(*pkt), 0,
+               (struct sockaddr *)peer, len);
+
+        fd_set fds;
+        FD_ZERO(&fds);
+        FD_SET(sock, &fds);
+
+        TIMEVAL tv;
+        tv.tv_sec = TIMEOUT_SEC;
+        tv.tv_usec = 0;
+
+        int ret = select(0, &fds, NULL, NULL, &tv);
+        if (ret > 0) {
+            struct packet ack;
+            recvfrom(sock, (char *)&ack, sizeof(ack), 0, NULL, NULL);
+            if (ack.type == TYPE_ACK && ack.seq == pkt->seq) {
+                return;
+            }
+        }
+        printf("[timeout] retransmit\n");
+    }
+}
+
+int main(int argc, char *argv[])
+{
     if (argc != 2) {
-        printf("Usage: %s <Ubuntu IPv6>\n", argv[0]);
+        printf("用法: %s <对方IPv6地址>\n", argv[0]);
         return 1;
     }
 
     WSADATA wsa;
-    WSAStartup(MAKEWORD(2,2), &wsa);
+    WSAStartup(MAKEWORD(2, 2), &wsa);
 
     SOCKET sock = socket(AF_INET6, SOCK_DGRAM, 0);
 
     struct sockaddr_in6 local = {0};
     local.sin6_family = AF_INET6;
-    local.sin6_port = htons(LOCAL_PORT);
     local.sin6_addr = in6addr_any;
-    bind(sock, (struct sockaddr*)&local, sizeof(local));
+    local.sin6_port = htons(PORT);
+    bind(sock, (struct sockaddr *)&local, sizeof(local));
 
     struct sockaddr_in6 peer = {0};
     peer.sin6_family = AF_INET6;
-    peer.sin6_port = htons(PEER_PORT);
+    peer.sin6_port = htons(PORT);
     inet_pton(AF_INET6, argv[1], &peer.sin6_addr);
 
-    int timeout = TIMEOUT_MS;
-    setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO,
-               (char*)&timeout, sizeof(timeout));
-
     uint8_t send_seq = 0;
-    uint8_t waiting_ack = 0;
+    uint8_t recv_seq = 0;
-    packet_t last_pkt;
+    struct packet pkt, rcv;
+
+    printf("Windows UDP IPv6 Stop-Wait Chat\n");
 
     while (1) {
-        /*  尝试接收 */
+        fd_set fds;
-        packet_t pkt;
+        FD_ZERO(&fds);
-        struct sockaddr_in6 from;
+        FD_SET(sock, &fds);
-        int fromlen = sizeof(from);
+        TIMEVAL tv = {0, 100000};
 
-        int n = recvfrom(sock, (char*)&pkt, sizeof(pkt), 0,
+        if (select(0, &fds, NULL, NULL, &tv) > 0) {
-                         (struct sockaddr*)&from, &fromlen);
+            recvfrom(sock, (char *)&rcv, sizeof(rcv), 0, NULL, NULL);
-
+            if (rcv.type == TYPE_DATA) {
-        if (n > 0) {
+                if (rcv.seq == recv_seq) {
-            if (pkt.type == TYPE_DATA) {
+                    printf("\npeer: %s\n", rcv.payload);
-                printf("\nPeer: %s", pkt.data);
+                    recv_seq ^= 1;
-
-                packet_t ack = {0};
-                ack.type = TYPE_ACK;
-                ack.seq = pkt.seq;
-
-                sendto(sock, (char*)&ack, sizeof(ack), 0,
-                       (struct sockaddr*)&peer, sizeof(peer));
                 }
-            else if (pkt.type == TYPE_ACK &&
+                rcv.type = TYPE_ACK;
-                     waiting_ack && pkt.seq == send_seq) {
+                sendto(sock, (char *)&rcv, sizeof(rcv), 0,
-                waiting_ack = 0;
+                       (struct sockaddr *)&peer, sizeof(peer));
+            }
+        }
+
+        printf(">> ");
+        if (!fgets(pkt.payload, sizeof(pkt.payload), stdin))
+            break;
+
+        pkt.seq = send_seq;
+        pkt.type = TYPE_DATA;
+
+        send_with_stopwait(sock, &peer, &pkt);
         send_seq ^= 1;
     }
-        }
 
-        /*  如果不在等 ACK，允许发送 */
+    closesocket(sock);
-        if (!waiting_ack) {
+    WSACleanup();
-            char buf[DATA_LEN];
+    return 0;
-            printf("You: ");
-            fflush(stdout);
-
-            if (fgets(buf, sizeof(buf), stdin) == NULL)
-                continue;
-
-            memset(&last_pkt, 0, sizeof(last_pkt));
-            last_pkt.type = TYPE_DATA;
-            last_pkt.seq = send_seq;
-            last_pkt.length = strlen(buf);
-            memcpy(last_pkt.data, buf, last_pkt.length);
-
-            sendto(sock, (char*)&last_pkt, sizeof(last_pkt), 0,
-                   (struct sockaddr*)&peer, sizeof(peer));
-
-            waiting_ack = 1;
-        } else {
-            sendto(sock, (char*)&last_pkt, sizeof(last_pkt), 0,
-                   (struct sockaddr*)&peer, sizeof(peer));
-            Sleep(TIMEOUT_MS);
-        }
-    }
 }