good starting point, finished the guide

1 files changed, 100 insertions, 0 deletions

diff --git a/client.c b/client.c
new file mode 100644
index 0000000..591d030
--- /dev/null
+++ b/client.c
@@ -0,0 +1,100 @@
+/*
+** 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, numbytesrecv, numbytessent;  
+    char buf[MAXDATASIZE];
+    struct addrinfo hints, *servinfo, *p;
+    int rv;
+    char s[INET6_ADDRSTRLEN];
+
+    if (argc != 3) {
+        fprintf(stderr,"usage: client hostname\n");
+        exit(1);
+    }
+
+    memset(&hints, 0, sizeof hints);
+    hints.ai_family = AF_INET; // only IPv4
+    hints.ai_socktype = SOCK_STREAM;
+
+    if ((rv = getaddrinfo(argv[2], 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 ((numbytesrecv = recv(sockfd, buf, MAXDATASIZE-1, 0)) == -1) {
+        perror("recv");
+        exit(1);
+    }
+
+    buf[numbytesrecv] = '\0';
+
+    printf("client: received '%s'\n",buf);
+
+    if ((numbytessent = send(sockfd, "Welcome", 7, 0)) == -1) {
+        perror("send");
+        exit(1);
+    }
+
+    buf[numbytessent] = '\0';
+
+    close(sockfd);
+
+    return 0;
+}
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