From 92fed4f21f69bc8e25c4e8e6c0a35010c3a8f154 Mon Sep 17 00:00:00 2001
From: xinghen <2593026969@qq.com>
Date: Fri, 26 Dec 2025 15:12:09 +0800
Subject: [PATCH] 1

---
 linux_chat.c   | 16 ++++++++++++----
 windows_chat.c | 24 ++++++++++++++++--------
 2 files changed, 28 insertions(+), 12 deletions(-)

diff --git a/linux_chat.c b/linux_chat.c
index f2b7bb1..e35e11c 100644
--- a/linux_chat.c
+++ b/linux_chat.c
@@ -10,12 +10,12 @@
 /* 停等协议发送（带超时重传） */
 void send_with_stopwait(int sock,
                         struct sockaddr_in6 *peer,
-                        struct packet *pkt)
+                        struct packet *pkt, int pkt_len)
 {
     socklen_t len = sizeof(*peer);
 
     while (1) {
-        sendto(sock, pkt, sizeof(*pkt), 0,
+        sendto(sock, pkt, pkt_len, 0,
                (struct sockaddr *)peer, len);
 
         fd_set fds;
@@ -66,6 +66,9 @@ int main(int argc, char *argv[])
     uint8_t recv_seq = 0;
     struct packet pkt, rcv;
 
+    memset(&pkt, 0, sizeof(pkt));
+    memset(&rcv, 0, sizeof(rcv));
+
     printf("Linux UDP IPv6 Stop-Wait Chat\n");
 
     while (1) {
@@ -77,13 +80,14 @@ int main(int argc, char *argv[])
 
         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, sizeof(rcv), 0,
+                sendto(sock, &rcv, 2, 0,
                        (struct sockaddr *)&peer, sizeof(peer));
             }
         }
@@ -93,10 +97,14 @@ int main(int argc, char *argv[])
         if (!fgets(pkt.payload, sizeof(pkt.payload), stdin))
             break;
 
+        size_t len = strlen(pkt.payload);
+        if (len > 0 && pkt.payload[len - 1] == '\n') pkt.payload[len - 1] = '\0';
+
         pkt.seq = send_seq;
         pkt.type = TYPE_DATA;
 
-        send_with_stopwait(sock, &peer, &pkt);
+        int pkt_len = 2 + strlen(pkt.payload) + 1;
+        send_with_stopwait(sock, &peer, &pkt, pkt_len);
         send_seq ^= 1;
     }
 
diff --git a/windows_chat.c b/windows_chat.c
index 3967cfc..c991470 100644
--- a/windows_chat.c
+++ b/windows_chat.c
@@ -9,13 +9,13 @@
 
 void send_with_stopwait(SOCKET sock,
                         struct sockaddr_in6 *peer,
-                        struct packet *pkt)
+                        struct packet *pkt, int pkt_len)
 {
-    int len = sizeof(*peer);
+    int addr_len = sizeof(*peer);
 
     while (1) {
-        sendto(sock, (char *)pkt, sizeof(*pkt), 0,
-               (struct sockaddr *)peer, len);
+        sendto(sock, (char *)pkt, pkt_len, 0,
+               (struct sockaddr *)peer, addr_len);
 
         fd_set fds;
         FD_ZERO(&fds);
@@ -25,7 +25,7 @@ void send_with_stopwait(SOCKET sock,
         tv.tv_sec = TIMEOUT_SEC;
         tv.tv_usec = 0;
 
-        int ret = select(0, &fds, NULL, NULL, &tv);
+        int ret = select(sock + 1, &fds, NULL, NULL, &tv);
         if (ret > 0) {
             struct packet ack;
             recvfrom(sock, (char *)&ack, sizeof(ack), 0, NULL, NULL);
@@ -64,6 +64,9 @@ int main(int argc, char *argv[])
     uint8_t recv_seq = 0;
     struct packet pkt, rcv;
 
+    memset(&pkt, 0, sizeof(pkt));
+    memset(&rcv, 0, sizeof(rcv));
+
     printf("Windows UDP IPv6 Stop-Wait Chat\n");
 
     while (1) {
@@ -72,15 +75,16 @@ int main(int argc, char *argv[])
         FD_SET(sock, &fds);
         TIMEVAL tv = {0, 100000};
 
-        if (select(0, &fds, NULL, NULL, &tv) > 0) {
+        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, sizeof(rcv), 0,
+                sendto(sock, (char *)&rcv, 2, 0,
                        (struct sockaddr *)&peer, sizeof(peer));
             }
         }
@@ -89,10 +93,14 @@ int main(int argc, char *argv[])
         if (!fgets(pkt.payload, sizeof(pkt.payload), stdin))
             break;
 
+        size_t len = strlen(pkt.payload);
+        if (len > 0 && pkt.payload[len - 1] == '\n') pkt.payload[len - 1] = '\0';
+
         pkt.seq = send_seq;
         pkt.type = TYPE_DATA;
 
-        send_with_stopwait(sock, &peer, &pkt);
+        int pkt_len = 2 + strlen(pkt.payload) + 1;
+        send_with_stopwait(sock, &peer, &pkt, pkt_len);
         send_seq ^= 1;
     }