Added tcp forwarder for postfix

Signed-off-by: Tyrolyean <tyrolyean@tyrolyean.net>

Makefile

@@ -33,7 +33,7 @@ $(DIRS_TARGET):
 	$(MKDIR_P) $@
 
 $(TARGET): $(OBJFILES)
-	$(CC) $(LDFLAGS) -o $@  $^ /usr/lib/libmilter.a
+	$(CC) $(LDFLAGS) -o $@  $^ 
  
 $(BUILDDIR)/%.o: $(SRCDIR)/%.c
 	$(CC) $(CFLAGS) -c -o $@ $<

include/config.h

@@ -17,6 +17,8 @@
 #ifndef CONFIG_H
 #define CONFIG_H
 
-extern char* socket_location;
+#include <stdint.h>
+
+extern uint16_t listen_port, forward_port;
 
 #endif /* CONFIG_H */

src/config.c

@@ -16,5 +16,4 @@
  */
 #include "config.h"
 
-char* socket_location = "/var/run/mailattach";
-
+uint16_t listen_port = 4269, forward_port = 4270;

src/main.c

@@ -12,25 +12,196 @@
 #include <sysexits.h>
 #include <unistd.h>
 #include <sys/stat.h>
+#include <netdb.h>
+#include <sys/types.h> 
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <poll.h>
+#include <pthread.h>
+
 
 #include "version.h"
 #include "config.h"
 #include "attach.h"
 
+/*
+ * error - wrapper for perror
+ */
+void error(char *msg) {
+  perror(msg);
+  exit(1);
+}
+
+
+struct client_info {
+	int fd;
+};
+
+void* client_handle_async(void* params){
+	
+	struct client_info * cli = params;
+	struct sockaddr_in serveraddr; /* server's addr */
+	int remote_fd;
+
+	remote_fd =  socket(AF_INET, SOCK_STREAM, 0);
+	if (remote_fd < 0){
+		error("ERROR opening client socket");
+	}
+
+	/* build the server's Internet address */
+	bzero((char *) &serveraddr, sizeof(serveraddr));
+	
+	serveraddr.sin_family = AF_INET;
+	serveraddr.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
+	serveraddr.sin_port = htons(forward_port);
+
+	/* connect: create a connection with the server */
+	if (connect(remote_fd,(struct sockaddr *) &serveraddr, 
+		sizeof(serveraddr)) < 0){
+		error("ERROR connecting");
+	}
+
+	int n; /* message byte size */
+	char buf[1024];
+	struct pollfd fds[2];
+	memset(fds, 0 , sizeof(fds));
+	fds[0].fd = cli->fd;
+	fds[0].events = POLLIN;
+	fds[1].fd = remote_fd;
+	fds[1].events = POLLIN;
+	
+	int timeout = (10 * 1000); /* 10 seconds */
+
+	while(poll(fds, 2, timeout) > 0){
+		for(size_t i = 0; i < 2; i++){
+			if(!(fds[i].revents & POLLIN)){
+				continue;
+
+			}
+			bzero(buf, sizeof(buf));
+			n = read(fds[i].fd, buf, sizeof(buf));
+			if (n <= 0) {
+				goto closeup;
+			}
+			printf("%lu: %s\n", i, buf);
+			write((fds[!i].fd), buf, n);
+			
+		}
+	}
+
+closeup:
+
+	printf("Disconnecting clients");
+	close(cli->fd);
+	close(remote_fd);
+	free(cli);
+	
+	return NULL;
+}
+
 int main(int argc, char* argv[]){
 	
-	FILE* logfile = fopen("/tmp/shit", "a+");
-	
-	fprintf(logfile, "INIT\n");
-	fprintf(logfile, "Arguments passed on:\n");
-	for(size_t i = 0; i < argc; i++){
-		fprintf(logfile, "\t%lu:%s\n",i, argv[i]);
+	printf("INIT\n");
+	printf("Arguments passed on:\n");
+	for(int i = 0; i < argc; i++){
+		printf("\t%i:%s\n",i, argv[i]);
 	}
-	char input[1024];
-	fread(input, sizeof(input), 1, stdin);
-	fprintf(logfile, input);
 	
-	fclose(logfile);
+	int parentfd; /* parent socket */
+	int childfd; /* child socket */
+	socklen_t clientlen; /* byte size of client's address */
+	struct sockaddr_in serveraddr; /* server's addr */
+	struct sockaddr_in clientaddr; /* client addr */
+	struct hostent *hostp; /* client host info */
+	char *hostaddrp; /* dotted decimal host addr string */
+	int optval; /* flag value for setsockopt */
+
+	/* 
+	* socket: create the parent socket 
+	*/
+	parentfd = socket(AF_INET, SOCK_STREAM, 0);
+	if (parentfd < 0){
+		error("ERROR opening socket");
+	}
+
+	/* setsockopt: Handy debugging trick that lets 
+	* us rerun the server immediately after we kill it; 
+	* otherwise we have to wait about 20 secs. 
+	* Eliminates "ERROR on binding: Address already in use" error. 
+	*/
+	optval = 1;
+	setsockopt(parentfd, SOL_SOCKET, SO_REUSEADDR, 
+	     (const void *)&optval , sizeof(int));
+
+	/*
+	* build the server's Internet address
+	*/
+	bzero((char *) &serveraddr, sizeof(serveraddr));
+
+	/* this is an Internet address */
+	serveraddr.sin_family = AF_INET;
+
+	/* let the system figure out our IP address */
+	serveraddr.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
+
+	/* this is the port we will listen on */
+	serveraddr.sin_port = htons((unsigned short)listen_port);
+
+	/* 
+	* bind: associate the parent socket with a port 
+	*/
+	if (bind(parentfd, (struct sockaddr *) &serveraddr, 
+	   sizeof(serveraddr)) < 0) {
+		error("ERROR on binding");
+	}
+
+	/* 
+	* listen: make this socket ready to accept connection requests 
+	*/
+	if (listen(parentfd, 5) < 0) /* allow 5 requests to queue up */ 
+	error("ERROR on listen");
+
+	/* 
+	* main loop: wait for a connection request, echo input line, 
+	* then close connection.
+	*/
+	clientlen = sizeof(clientaddr);
+	char hostaddr_str[20];
+	inet_ntop(AF_INET,(struct sockaddr *) &serveraddr, hostaddr_str, 20);
+	printf("Listening for clients on port %u\n",  listen_port);
+	while (1) {
+
+		/* 
+		* accept: wait for a connection request 
+		*/
+		childfd = accept(parentfd, (struct sockaddr *) &clientaddr, &clientlen);
+		if (childfd < 0) 
+			error("ERROR on accept");
+
+		/* 
+		* gethostbyaddr: determine who sent the message 
+		*/
+		hostp = gethostbyaddr((const char *)&clientaddr.sin_addr.s_addr, 
+				  sizeof(clientaddr.sin_addr.s_addr), AF_INET);
+		if (hostp == NULL)
+			error("ERROR on gethostbyaddr");
+		hostaddrp = inet_ntoa(clientaddr.sin_addr);
+		if (hostaddrp == NULL)
+			error("ERROR on inet_ntoa\n");
+		printf("server established connection with %s (%s) fd %i\n", 
+		   hostp->h_name, hostaddrp, childfd);
+		
+		struct client_info* cli = malloc(sizeof(struct client_info));
+		memset(cli, 0, sizeof(struct client_info));
+		cli->fd = childfd;
+		pthread_t executing_thread;
+		int status = pthread_create(&executing_thread, NULL,
+			client_handle_async, cli);
+		if(status < 0){
+			error("Failed to create thread");
+		}
+	}
 
 
 	return EX_TEMPFAIL;