init

diff --git a/client.c b/client.c
new file mode 100644 (file)
index 0000000..b494807
--- /dev/null
+++ b/client.c
@@ -0,0 +1,94 @@
+/*
+** client.c -- a stream socket client demo
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <errno.h>
+#include <string.h>
+#include <netdb.h>
+#include <sys/types.h>
+#include <netinet/in.h>
+#include <sys/socket.h>
+
+#include <arpa/inet.h>
+
+#define PORT "3490" // the port client will be connecting to 
+
+#define MAXDATASIZE 100 // max number of bytes we can get at once 
+
+// get sockaddr, IPv4 or IPv6:
+void *get_in_addr(struct sockaddr *sa)
+{
+       if (sa->sa_family == AF_INET) {
+               return &(((struct sockaddr_in*)sa)->sin_addr);
+       }
+
+       return &(((struct sockaddr_in6*)sa)->sin6_addr);
+}
+
+int main(int argc, char *argv[])
+{
+       int sockfd, numbytes;  
+       char buf[MAXDATASIZE];
+       struct addrinfo hints, *servinfo, *p;
+       int rv;
+       char s[INET6_ADDRSTRLEN];
+
+       if (argc != 2) {
+           fprintf(stderr,"usage: client hostname\n");
+           exit(1);
+       }
+
+       memset(&hints, 0, sizeof hints);
+       hints.ai_family = AF_UNSPEC;
+       hints.ai_socktype = SOCK_STREAM;
+
+       if ((rv = getaddrinfo(argv[1], PORT, &hints, &servinfo)) != 0) {
+               fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(rv));
+               return 1;
+       }
+
+       // loop through all the results and connect to the first we can
+       for(p = servinfo; p != NULL; p = p->ai_next) {
+               if ((sockfd = socket(p->ai_family, p->ai_socktype,
+                               p->ai_protocol)) == -1) {
+                       perror("client: socket");
+                       continue;
+               }
+
+               if (connect(sockfd, p->ai_addr, p->ai_addrlen) == -1) {
+                       close(sockfd);
+                       perror("client: connect");
+                       continue;
+               }
+
+               break;
+       }
+
+       if (p == NULL) {
+               fprintf(stderr, "client: failed to connect\n");
+               return 2;
+       }
+
+       inet_ntop(p->ai_family, get_in_addr((struct sockaddr *)p->ai_addr),
+                       s, sizeof s);
+       printf("client: connecting to %s\n", s);
+
+       freeaddrinfo(servinfo); // all done with this structure
+
+       if ((numbytes = recv(sockfd, buf, MAXDATASIZE-1, 0)) == -1) {
+           perror("recv");
+           exit(1);
+       }
+
+       buf[numbytes] = '\0';
+
+       printf("client: received '%s'\n",buf);
+
+       close(sockfd);
+
+       return 0;
+}
+

diff --git a/server.c b/server.c
new file mode 100644 (file)
index 0000000..74cf914
--- /dev/null
+++ b/server.c
@@ -0,0 +1,128 @@
+/*
+** server.c -- a stream socket server demo
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <errno.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <netdb.h>
+#include <arpa/inet.h>
+#include <sys/wait.h>
+#include <signal.h>
+
+#define PORT "3490"  // the port users will be connecting to
+
+#define BACKLOG 10      // how many pending connections queue will hold
+
+void sigchld_handler(int s)
+{
+       while(waitpid(-1, NULL, WNOHANG) > 0);
+}
+
+// get sockaddr, IPv4 or IPv6:
+void *get_in_addr(struct sockaddr *sa)
+{
+       if (sa->sa_family == AF_INET) {
+               return &(((struct sockaddr_in*)sa)->sin_addr);
+       }
+
+       return &(((struct sockaddr_in6*)sa)->sin6_addr);
+}
+
+int main(void)
+{
+       int sockfd, new_fd;  // listen on sock_fd, new connection on new_fd
+       struct addrinfo hints, *servinfo, *p;
+       struct sockaddr_storage their_addr; // connector's address information
+       socklen_t sin_size;
+       struct sigaction sa;
+       int yes=1;
+       char s[INET6_ADDRSTRLEN];
+       int rv;
+
+       memset(&hints, 0, sizeof hints);
+       hints.ai_family = AF_UNSPEC;
+       hints.ai_socktype = SOCK_STREAM;
+       hints.ai_flags = AI_PASSIVE; // use my IP
+
+       if ((rv = getaddrinfo(NULL, PORT, &hints, &servinfo)) != 0) {
+               fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(rv));
+               return 1;
+       }
+
+       // loop through all the results and bind to the first we can
+       for(p = servinfo; p != NULL; p = p->ai_next) {
+               if ((sockfd = socket(p->ai_family, p->ai_socktype,
+                               p->ai_protocol)) == -1) {
+                       perror("server: socket");
+                       continue;
+               }
+
+               if (setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &yes,
+                               sizeof(int)) == -1) {
+                       perror("setsockopt");
+                       exit(1);
+               }
+
+               if (bind(sockfd, p->ai_addr, p->ai_addrlen) == -1) {
+                       close(sockfd);
+                       perror("server: bind");
+                       continue;
+               }
+
+               break;
+       }
+
+       if (p == NULL)  {
+               fprintf(stderr, "server: failed to bind\n");
+               return 2;
+       }
+
+       freeaddrinfo(servinfo); // all done with this structure
+
+       if (listen(sockfd, BACKLOG) == -1) {
+               perror("listen");
+               exit(1);
+       }
+
+       sa.sa_handler = sigchld_handler; // reap all dead processes
+       sigemptyset(&sa.sa_mask);
+       sa.sa_flags = SA_RESTART;
+       if (sigaction(SIGCHLD, &sa, NULL) == -1) {
+               perror("sigaction");
+               exit(1);
+       }
+
+       printf("server: waiting for connections...\n");
+
+       while(1) {  // main accept() loop
+               sin_size = sizeof their_addr;
+               new_fd = accept(sockfd, (struct sockaddr *)&their_addr, &sin_size);
+               if (new_fd == -1) {
+                       perror("accept");
+                       continue;
+               }
+
+               inet_ntop(their_addr.ss_family,
+                       get_in_addr((struct sockaddr *)&their_addr),
+                       s, sizeof s);
+               printf("server: got connection from %s\n", s);
+
+               if (!fork()) { // this is the child process
+                       close(sockfd); // child doesn't need the listener
+                       if (send(new_fd, "Hello, world!", 13, 0) == -1)
+                               perror("send");
+                       close(new_fd);
+                       exit(0);
+               }
+               close(new_fd);  // parent doesn't need this
+       }
+
+       return 0;
+}
+