1 files changed, 206 insertions, 0 deletions
diff --git a/proxy.c b/proxy.c
new file mode 100644
index 0000000..32ae0e2
--- /dev/null
+++ b/proxy.c
@@ -0,0 +1,206 @@
+#include <pthread.h>
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+#include <ctype.h>
+
+#include <unistd.h>
+
+#include <poll.h>
+
+#include <sys/types.h>
+
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <netinet/tcp.h>
+#include <netdb.h>
+
+static const char *name;
+
+typedef struct
+{
+    int         sock_fd;
+    const char  *remote_host;
+    const char  *remote_port;
+} ThreadArg;
+
+static void Error(const char *call)
+{
+    fprintf(stderr, "%s:", name);
+    perror(call);
+    exit(EXIT_FAILURE);
+}
+
+static int Connect(const char *n, const char *p)
+{
+    struct addrinfo *addr, *addr_p;
+    struct addrinfo hints = {0};
+    int status;
+    int sock = -1;
+
+    hints.ai_family = PF_UNSPEC;
+    hints.ai_socktype = SOCK_STREAM;
+
+    status = getaddrinfo(n, p, &hints, &addr);
+
+    if (status)
+    {
+	fprintf(stderr, "%s: %s\n", name, gai_strerror(status));
+	exit(EXIT_FAILURE);
+    }
+
+    for(addr_p = addr; addr_p && sock == -1; addr_p = addr_p->ai_next)
+    {
+        sock = socket(addr_p->ai_family,
+                      addr_p->ai_socktype,
+                      addr_p->ai_protocol);
+
+        if (sock != -1)
+        {
+            if (connect(sock, addr_p->ai_addr, addr_p->ai_addrlen) == -1)
+            {
+                close(sock);
+                sock = -1;
+            }
+        }
+    }
+
+    if (sock == -1)
+    {
+        fprintf(stderr, "%s: Failed to connect to %s:%s\n", name, n, p);
+        exit(EXIT_FAILURE);
+    }
+
+    return sock;
+}
+
+static int Server(int p)
+{
+    struct sockaddr_in addr;
+    int sock_fd;
+
+    if ((sock_fd = socket(AF_INET, SOCK_STREAM, 0)) == -1)
+    {
+	Error("socket");
+    }
+
+    /* Bind port to address
+    */
+    addr.sin_family=AF_INET;
+    addr.sin_addr.s_addr=INADDR_ANY;
+    addr.sin_port=htons(p);
+
+    if (bind(sock_fd,(void*)&addr,sizeof(addr))==-1)
+    {
+	Error("bind");
+    }
+
+    if (listen(sock_fd,5)==-1)
+    {
+	Error("listen");
+    }
+
+    return sock_fd;
+}
+
+static void *ThreadCode(void *arg)
+{
+    int fd;
+    ThreadArg *ta = arg;
+    struct pollfd fds[2] = {0};
+    int done = 0;
+
+    fd = Connect(ta->remote_host, ta->remote_port);
+
+    fds[0].fd = ta->sock_fd;
+    fds[0].events = POLLRDNORM;
+    fds[1].fd = fd;
+    fds[1].events = POLLRDNORM;
+
+    while(!done)
+    {
+        int f;
+
+        if (poll(fds, 2, -1) == -1)
+        {
+            Error("poll");
+        }
+
+        for(int f = 0; f < 2; f++)
+        {
+            if (fds[f].revents & POLLRDNORM)
+            {
+                char buff[1024];
+                int rd;
+
+                if ((rd = read(fds[f].fd, buff, sizeof buff)) < 1)
+                {
+                   done = 1;
+                }
+                else
+                {
+                    write(fds[f ^ 1].fd, buff, rd);
+                }
+            }
+        }
+    }
+
+    close(ta->sock_fd);
+    close(fd);
+
+    free(ta);
+
+    return NULL;
+}
+
+int main(int argc, char *argv[])
+{
+    struct sockaddr_in addr;
+    char buff[1025];
+    int len;
+    socklen_t addrlen;
+    int sock_fd;
+    int connect_fd;
+
+    name=argv[0];
+
+    if (argc != 4)
+    {
+	fprintf(stderr,"%s: usage %s local_port remote_address remote_port\n",
+                        name, name);
+	exit(1);
+    }
+
+    sock_fd = Server((short)atoi(argv[1]));
+
+    printf("%s: socket bound\n",name);
+
+    while(1)
+    {
+        pthread_t thread;
+        ThreadArg *arg;
+
+	printf("%s: accepting\n",name);
+
+	if ((connect_fd=accept(sock_fd,NULL,0))==-1)
+	{
+	    Error("accept");
+	}
+
+        if (!(arg = malloc(sizeof *arg)))
+        {
+            Error("malloc");
+        }
+
+        arg->sock_fd = connect_fd;
+        arg->remote_host = argv[2];
+        arg->remote_port = argv[3];
+
+        pthread_create(&thread, NULL, ThreadCode, arg);
+        pthread_detach(thread);
+    }
+
+    return EXIT_SUCCESS;
+}