From a7d55e699e8b9c414563a0cd98f4eb3bc43c76a9 Mon Sep 17 00:00:00 2001
From: Luiz Capitulino <lcapitulino@gmail.com>
Date: Thu, 13 Jan 2011 14:19:51 -0200
Subject: [PATCH] Introduce old redir program

Signed-off-by: Luiz Capitulino <lcapitulino@gmail.com>
---
 redir/Makefile |   6 ++
 redir/redir.c  | 199 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 205 insertions(+)
 create mode 100644 redir/Makefile
 create mode 100644 redir/redir.c

diff --git a/redir/Makefile b/redir/Makefile
new file mode 100644
index 0000000..bd8c3b1
--- /dev/null
+++ b/redir/Makefile
@@ -0,0 +1,6 @@
+
+redir: redir.c
+	$(CC) -Wall -o $@ $+
+
+clean:
+	rm -f redir *~ *.o
diff --git a/redir/redir.c b/redir/redir.c
new file mode 100644
index 0000000..d0161df
--- /dev/null
+++ b/redir/redir.c
@@ -0,0 +1,199 @@
+/*
+ * Simple TCP redirector
+ *
+ * Luiz Fernando N. Capitulino <lcapitulino@gmail.com>
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <signal.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/select.h>
+#include <sys/wait.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+
+static void die(const char *s)
+{
+    perror(s);
+    exit(1);
+}
+
+static void help(void)
+{
+    printf("redir <source IP>:<source port> <destination IP>:<destination port>\n");
+    exit(1);
+}
+
+static void cleanup_child(int signr)
+{
+    wait(NULL);
+}
+
+static int read_user_addr(struct sockaddr_in *addr, const char *addr_str)
+{
+    int ret = -1;
+    char *p, *addr_str2;
+
+    addr_str2 = strdup(addr_str);
+    p = strchr(addr_str2, ':');
+    if (!p) {
+        goto out;
+    }
+
+    *p = '\0';
+    if (!inet_aton(addr_str2, &addr->sin_addr)) {
+        goto out;
+    }
+
+    p++;
+    if (p == '\0') {
+        goto out;
+    }
+
+    addr->sin_port = htons(strtol(p, NULL, 10));
+    addr->sin_family = AF_INET;
+    ret = 0;
+
+out:
+    free(addr_str2);
+    return ret;
+}
+
+static int redir(int sfd, int dfd)
+{
+    unsigned char buf[4096];
+    size_t count, total, idx;
+
+    memset(buf, 0, sizeof(buf));
+
+    count = read(sfd, buf, sizeof(buf));
+    if (!count) {
+        return 1;
+    }
+
+    idx = 0;
+    total = count;
+    for (;;) {
+        count = write(dfd, buf + idx, total);
+        if (count < 0) {
+            die("write()");
+        }
+
+        total -= count;
+        if (!total) {
+            return 0;
+        }
+        idx += count;
+    }
+}
+
+static void handle_new_client(int cfd, struct sockaddr_in *client_add,
+                              struct sockaddr_in *dest_addr)
+{
+    int ret, dfd, nfds;
+
+    dfd = socket(AF_INET, SOCK_STREAM, 0);
+    if (dfd < 0) {
+        die("socket()");
+    }
+
+    ret = connect(dfd, (struct sockaddr *) dest_addr,
+                  sizeof(struct sockaddr_in));
+    if (dfd < 0) {
+        die("connect()");
+    }
+
+    nfds = cfd >= dfd ? cfd : dfd;
+    for (;;) {
+        fd_set rfds;
+
+        FD_ZERO(&rfds);
+        FD_SET(cfd, &rfds);
+        FD_SET(dfd, &rfds);
+
+        ret = select(nfds + 1, &rfds, NULL, NULL, 0);
+        if (ret < 0) {
+            die("select()");
+        } else if (FD_ISSET(cfd, &rfds)) {
+            if (redir(cfd, dfd)) {
+                return;
+            }
+        } else if (FD_ISSET(dfd, &rfds)) {
+            if (redir(dfd, cfd)) {
+                return;
+            }
+        } else {
+            abort();
+        }
+    }
+
+    close(dfd);
+}
+
+int main(int argc, const char *argv[])
+{
+    struct sockaddr_in src_addr, dest_addr, client_addr;
+    socklen_t dest_addr_sz;
+    int err, sfd, cfd;
+
+    if (argc != 3) {
+        help();
+    }
+
+    err = read_user_addr(&src_addr, argv[1]);
+    if (err) {
+        help();
+    }
+
+    err = read_user_addr(&dest_addr, argv[2]);
+    if (err) {
+        help();
+    }
+
+    signal(SIGCHLD, cleanup_child);
+
+    sfd = socket(AF_INET, SOCK_STREAM, 0);
+    if (sfd < 0) {
+        die("socket()");
+    }
+
+    err = bind(sfd, (struct sockaddr *) &src_addr, sizeof(struct sockaddr_in));
+    if (err) {
+        die("bind()");
+    }
+
+    err = listen(sfd, 2);
+    if (err) {
+        die("listen()");
+    }
+
+    for (;;) {
+        pid_t pid;
+
+        dest_addr_sz = sizeof(struct sockaddr_in);
+        cfd = accept(sfd, (struct sockaddr *) &client_addr, &dest_addr_sz);
+        if (cfd < 0) {
+            die("accept()");
+        }
+
+        fprintf(stderr, "-> New connection from: %s:%d\n",
+                inet_ntoa(client_addr.sin_addr), ntohs(client_addr.sin_port));
+
+        pid = fork();
+        if (pid < 0) {
+            perror("fork()");
+        } else if (pid == 0) {
+            /* child */
+            handle_new_client(cfd, &client_addr, &dest_addr);
+            exit(0);
+        }
+
+        /* parent */
+        close(cfd);
+    }
+
+    return 0;
+}
-- 
2.11.4.GIT