Removed submodules

lab5-net/client.c

@@ -0,0 +1,108 @@
+#include <arpa/inet.h>
+#include <assert.h>
+#include <netdb.h>
+#include <netinet/in.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <unistd.h>
+
+#include "client.h"
+
+#define BUFFER_MAX_SIZE 4096
+
+/* Given a struct with server information, return a dynamically allocated
+   string of the IP address in dotted decimal or colon hexadecimal notation.
+   Consult Chapter 4, as well as /usr/include/netdb.h and
+   /usr/include/arpa/inet.h as needed. Use inet_ntop() to get the formatted
+   string based on the address's ai_addr field.
+ */
+char *
+addr_string (struct addrinfo *server)
+{
+  // Return safely in case server is NULL:
+  if (server == NULL)
+    return strdup ("no address information");
+
+  size_t addrlen
+      = server->ai_family == AF_INET6 ? INET6_ADDRSTRLEN : INET_ADDRSTRLEN;
+  char *buffer = calloc (addrlen, sizeof (char));
+
+  void *addr;
+  if (server->ai_family == AF_INET)
+    addr = &((struct sockaddr_in *)server->ai_addr)->sin_addr;
+  else
+    addr = &((struct sockaddr_in6 *)server->ai_addr)->sin6_addr;
+
+  inet_ntop (server->ai_family, addr, buffer, addrlen);
+  return buffer;
+}
+
+/* Given the server address info, return a dynamically allocated string with
+   its transport-layer protocol, IP version, and IP address. For instance,
+   querying jmu.edu over TCP/IPv4 should return:
+     "TCP IPv4 134.126.10.50"
+   Use addr_string() to get the formatted address string, concatenate it to
+   the string to return, then free the result from addr_string(). If the
+   passed server parameter is NULL, use strdup() to return a dynamically
+   allocated copy of "no address information".
+
+   NOTE: When distinguishing TCP and UDP, you should be checking the
+   server->ai_socktype field, not server->ai_protocol. The test cases do not
+   set the server->ai_protocol, which is sometimes not used in practice.
+ */
+char *
+serv_string (struct addrinfo *server)
+{
+  // Return safely in case server is NULL:
+  if (server == NULL)
+    return strdup ("no address information");
+
+  size_t addrlen
+      = server->ai_family == AF_INET6 ? INET6_ADDRSTRLEN : INET_ADDRSTRLEN;
+
+  char *buffer = calloc (10 + addrlen, sizeof (char));
+
+  char *proto = server->ai_socktype == SOCK_STREAM ? "TCP" : "UDP";
+  char *ipver = server->ai_family == AF_INET ? "IPv4" : "IPv6";
+
+  char *addr = addr_string (server);
+
+  snprintf (buffer, 10 + addrlen, "%s %s %s", proto, ipver, addr);
+
+  free (addr);
+
+  return buffer;
+}
+
+/* Given a hostname string, use getaddrinfo() to query DNS for the specified
+   protocol parameters. Boolean values indicate whether or not to use IPv6
+   (as opposed to IPv4) or TCP (as opposed to UDP). For this lab, the protocol
+   will only be "http", though it could be others in a more complete
+   implementation. Return the pointer to the linked list of server results.
+ */
+struct addrinfo *
+get_server_list (const char *hostname, const char *proto, bool tcp, bool ipv6)
+{
+  struct addrinfo hints = { 0 };
+  struct addrinfo *server_list = NULL;
+
+  hints.ai_family = ipv6 ? AF_INET6 : AF_INET;
+
+  if (tcp)
+    {
+      hints.ai_socktype = SOCK_STREAM;
+      hints.ai_protocol = IPPROTO_TCP;
+    }
+  else
+    {
+      hints.ai_socktype = SOCK_DGRAM;
+      hints.ai_protocol = IPPROTO_UDP;
+    }
+
+  getaddrinfo (hostname, proto, &hints, &server_list);
+
+  return server_list;
+}