Impl printing source address

1 files changed, 17 insertions, 4 deletions

diff --git a/server.c b/server.c
index e35a9b5..7288eca 100644
--- a/server.c
+++ b/server.c
@@ -15,7 +15,7 @@ int main(void)
     }
     struct sockaddr_in const serveraddr = {
         .sin_family = AF_INET,
-        .sin_port = htons(50037),
+        .sin_port = htons(50037u),
         .sin_addr.s_addr = htonl(INADDR_ANY),
     };
     if (bind(fd, (struct sockaddr *)&serveraddr, sizeof(serveraddr)) < 0) {
@@ -23,14 +23,27 @@ int main(void)
         return 1;
     }
     for (;;) {
+        struct sockaddr_in source_address;
         char buffer[200];
-        int const length = recvfrom(fd, buffer, sizeof(buffer) - 1, 0, NULL, 0);
+        socklen_t source_address_len = sizeof(source_address);
+        int const length = recvfrom(
+                fd,
+                buffer,
+                sizeof(buffer) - 1,
+                0,
+                (struct sockaddr*)&source_address,
+                &source_address_len);
         if (length < 0) {
             perror("recvfrom failed");
             break;
         }
-        buffer[length] = '\0';
-        printf("%d bytes: '%s'\n", length, buffer);
+        uint32_t const addr = ntohl(source_address.sin_addr.s_addr);
+        uint8_t const a0 = addr >> 24;
+        uint8_t const a1 = addr >> 16;
+        uint8_t const a2 = addr >> 8;
+        uint8_t const a3 = addr;
+        printf("%d bytes: '%.*s' from %u.%u.%u.%u:%u\n",
+                length, (int)length, buffer, a0, a1, a2, a3, source_address.sin_port);
     }
     close(fd);
 }