Lab10: add tcp client/server

lab10/client_tcp.c

@@ -0,0 +1,61 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netdb.h>
+#include <unistd.h>
+#include <string.h>
+
+int client_tcp() {
+    char* hostname = "localhost";
+    char* port = "9004";
+
+    struct addrinfo hints = {0};
+    hints.ai_family = AF_INET;
+    hints.ai_socktype = SOCK_STREAM;
+    hints.ai_protocol = IPPROTO_TCP;
+
+    struct addrinfo* res;
+    int err_ret = getaddrinfo(hostname, port, &hints, &res);
+
+    if (err_ret != 0) {
+        fprintf(stderr, "getaddrinfo got error code: %d\n", err_ret);
+        return -1;
+    }
+
+    int sfd = -1;
+    for (struct addrinfo* i = res; i != NULL; i = i->ai_next) {
+        sfd = socket(i->ai_family, i->ai_socktype, i->ai_protocol);
+        if (sfd == -1) {
+            perror("socket");
+            continue;
+        }
+
+        int connect_err = connect(sfd, i->ai_addr, i->ai_addrlen);
+        if (connect_err == -1) {
+            perror("connect client tcp");
+            continue;
+        }
+        break;
+    }
+
+    freeaddrinfo(res);
+    if (sfd == -1) {
+        fprintf(stderr, "couldn't create client socket\n");
+        return -1;
+    }
+    return sfd;
+}
+
+int main(void) {
+    int sfd_client = client_tcp();
+
+    char* my_string = "message from tcp client";
+    write(sfd_client, my_string, strlen(my_string) + 1);
+
+    char buf[1000];
+    read(sfd_client, buf, 1000);
+
+    printf("Client recieved from server: `%s`\n", buf);
+    close(sfd_client);
+}

lab10/server_tcp.c

@@ -0,0 +1,93 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netdb.h>
+#include <unistd.h>
+#include <string.h>
+
+int server_tcp() {
+    char* hostname = "localhost";
+    char* port = "9004";
+
+    struct addrinfo hints = {0};
+    hints.ai_family = AF_INET;
+    hints.ai_socktype = SOCK_STREAM;
+    hints.ai_protocol = IPPROTO_TCP;
+    hints.ai_flags = AI_PASSIVE;
+
+    struct addrinfo* res;
+    int err_ret = getaddrinfo(hostname, port, &hints, &res);
+    if (err_ret != 0) {
+        fprintf(stderr, "getaddrinfo got error code: %d\n", err_ret);
+        return -1;
+    }
+
+    int sfd = -1;
+    for (struct addrinfo* i = res; i != NULL; i = i->ai_next) {
+        sfd = socket(i->ai_family, i->ai_socktype, i->ai_protocol);
+        if (sfd == -1) {
+            perror("socket");
+            continue;
+        }
+
+        int err_ = bind(sfd, i->ai_addr, i->ai_addrlen);
+        if (err_ == -1) {
+            perror("bind server tcp");
+            close(sfd);
+            continue;
+        }
+
+        err_ = listen(sfd, 100);
+        if (err_ == -1) {
+            perror("listen server tcp");
+            close(sfd);
+            continue;
+        }
+
+        break;
+    }
+
+    freeaddrinfo(res);
+    return sfd;
+}
+
+void* echo_server(int sfd_server, int sfd_client) {
+    printf("socket server: %d\n", sfd_server);
+    printf("socket client: %d\n", sfd_client);
+
+    char buf[1000];
+    int len;
+    while (1) {
+        len = read(sfd_client, buf, 1000);
+
+        if (len == 0) {
+            continue;
+        }
+
+        printf("Got length: %d\n", len);
+        printf("Server received message: `%s`\n", buf);
+        break;
+    }
+
+    char* new_msg = "Some new string from the server";
+    write(sfd_client, new_msg, strlen(new_msg) + 1);
+
+    close(sfd_client);
+    return NULL;
+}
+
+
+int main(void) {
+    int sfd_server = server_tcp();
+    int sfd_client = accept(sfd_server, NULL, NULL);
+
+    if (sfd_client == -1) {
+        perror("accept server tcp");
+        return 1;
+    }
+
+    echo_server(sfd_server, sfd_client);
+
+    close(sfd_server);
+}