Rewrite args parsing to prepare for libpcap.

7 files changed, 121 insertions, 30 deletions

diff --git a/src/checksum.h b/src/checksum.h
index 74fe69f..192d538 100644
--- a/src/checksum.h
+++ b/src/checksum.h
@@ -1,3 +1,6 @@
+#ifndef CHECKSUM_H
+#define CHECKSUM_H
+
 #include <stdint.h>
 
 struct sockaddr;
@@ -14,3 +17,5 @@ uint16_t csum_partial(const void *buff, int len, uint16_t wsum);
  * otherwise identical to csum_partial.
  */
 uint16_t csum_sockaddr_partial(const struct sockaddr *addr, int incl_port, uint16_t wsum);
+
+#endif
diff --git a/src/client.c b/src/client.c
index 733ffa0..1517481 100644
--- a/src/client.c
+++ b/src/client.c
@@ -23,8 +23,7 @@
 #define PORTS_IN_INT (sizeof(int) * CHAR_BIT)
 
 struct c_data {
-    const char *r_host;
-    const char *r_port;
+    const struct common_data *common_data;
     struct o_c_sock *o_socks_by_caddr;
     struct o_c_rsock *o_rsocks;
     struct sockaddr_storage pkt_addr;
@@ -410,9 +409,9 @@ static inline struct o_c_sock * c_sock_init(EV_P_ struct c_data *c_data) {
     struct o_c_sock *sock = NULL;
 
     struct addrinfo *res;
-    DBG("looking up [%s]:%s", c_data->r_host, c_data->r_port);
+    DBG("looking up [%s]:%s", c_data->common_data->remote_host, c_data->common_data->remote_port);
     // TODO: make this asynchronous
-    int r = getaddrinfo(c_data->r_host, c_data->r_port, NULL, &res);
+    int r = getaddrinfo(c_data->common_data->remote_host, c_data->common_data->remote_port, NULL, &res);
     if (r) {
         fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(r));
         goto err;
@@ -565,18 +564,17 @@ static void c_finish(EV_P_ ev_signal *w __attribute__((unused)), int revents __a
     ev_break(EV_A_ EVBREAK_ALL);
 }
 
-int start_client(const char *s_host, const char *s_port, const char *r_host, const char *r_port) {
+int start_client(const struct common_data *common_data) {
     struct addrinfo *res;
-    int r = getaddrinfo(s_host, s_port, NULL, &res);
+    int r = getaddrinfo(common_data->listen_host, common_data->listen_port, NULL, &res);
     if (r) {
         fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(r));
         return 3;
     }
 
     struct c_data c_data = {
-        .s_addrlen = res->ai_addrlen,
-        .r_host = r_host,
-        .r_port = r_port
+        .common_data = common_data,
+        .s_addrlen = res->ai_addrlen
     };
 
     c_data.s_sock = socket(res->ai_family, SOCK_DGRAM, 0);
@@ -597,13 +595,13 @@ int start_client(const char *s_host, const char *s_port, const char *r_host, con
         return 4;
     }
 
-    global_c_data = &c_data;
-    atexit(c_cleanup);
-
     struct ev_loop *loop = EV_DEFAULT;
     ev_io s_watcher;
     ev_signal iwatcher, twatcher;
 
+    global_c_data = &c_data;
+    atexit(c_cleanup);
+
     s_watcher.data = &c_data;
 
     ev_io_init(&s_watcher, cs_cb, c_data.s_sock, EV_READ);
diff --git a/src/client.h b/src/client.h
index 69d4c7d..72c86fb 100644
--- a/src/client.h
+++ b/src/client.h
@@ -1 +1,6 @@
-int start_client(const char *s_host, const char *s_port, const char *r_host, const char *r_port);
+#ifndef CLIENT_H
+#define CLIENT_H
+#include "common.h"
+
+int start_client(const struct common_data *);
+#endif
diff --git a/src/common.h b/src/common.h
index fea0db7..9dd7318 100644
--- a/src/common.h
+++ b/src/common.h
@@ -1,3 +1,6 @@
+#ifndef COMMON_H
+#define COMMON_H
+
 #ifdef DEBUG
 #define DBG(...) do { fprintf(stderr, __VA_ARGS__); putc('\n', stderr); } while (0)
 #else
@@ -7,3 +10,14 @@
 #define IN_ADDR_PORT(addr) (((struct sockaddr_in *)addr)->sin_port)
 
 extern int free_mem_on_exit;
+extern void *libpcap;
+
+struct common_data {
+    const char *listen_host;
+    const char *listen_port;
+    const char *remote_host;
+    const char *remote_port;
+    const char *device;
+};
+
+#endif
diff --git a/src/server.c b/src/server.c
index 382e675..b9c2783 100644
--- a/src/server.c
+++ b/src/server.c
@@ -20,10 +20,9 @@
 #include "uthash.h"
 
 struct s_data {
+    const struct common_data *common_data;
     struct sockaddr *s_addr;
     struct sockaddr_storage pkt_addr;
-    const char *r_host;
-    const char *r_port;
     struct o_s_sock *o_socks_by_caddr;
     int s_sock;
     socklen_t s_addrlen;
@@ -299,7 +298,7 @@ static void ss_cb(EV_P_ ev_io *w, int revents __attribute__((unused))) {
             sock->status = TCP_ESTABLISHED;
 
             struct addrinfo *res;
-            r = getaddrinfo(s_data->r_host, s_data->r_port, NULL, &res);
+            r = getaddrinfo(s_data->common_data->remote_host, s_data->common_data->remote_port, NULL, &res);
             if (r) {
                 fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(r));
                 ev_break(EV_A_ EVBREAK_ONE);
@@ -375,9 +374,9 @@ static void s_finish(EV_P_ ev_signal *w __attribute__((unused)), int revents __a
     ev_break(EV_A_ EVBREAK_ALL);
 }
 
-int start_server(const char *s_host, const char *s_port, const char *r_host, const char *r_port) {
+int start_server(const struct common_data *common_data) {
     struct addrinfo *res;
-    int r = getaddrinfo(s_host, s_port, NULL, &res);
+    int r = getaddrinfo(common_data->listen_host, common_data->listen_port, NULL, &res);
     if (r) {
         fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(r));
         return 1;
@@ -386,10 +385,9 @@ int start_server(const char *s_host, const char *s_port, const char *r_host, con
     char proto[] = { 0, IPPROTO_TCP };
 
     struct s_data s_data = {
+        .common_data = common_data,
         .s_addr = res->ai_addr,
         .s_addrlen = res->ai_addrlen,
-        .r_host = r_host,
-        .r_port = r_port,
         .csum_p = csum_sockaddr_partial(res->ai_addr, 1,
                 csum_partial(&proto, sizeof(proto), 0))
     };
diff --git a/src/server.h b/src/server.h
index 3157173..80fb26b 100644
--- a/src/server.h
+++ b/src/server.h
@@ -1 +1,8 @@
-int start_server(const char *s_addr, const char *s_port, const char *r_addr, const char *r_port);
+#ifndef SERVER_H
+#define SERVER_H
+
+#include "common.h"
+
+int start_server(const struct common_data *);
+
+#endif
diff --git a/src/udpastcp.c b/src/udpastcp.c
index fa8fea2..31d2d50 100644
--- a/src/udpastcp.c
+++ b/src/udpastcp.c
@@ -1,17 +1,78 @@
+#include <dlfcn.h>
 #include <stdlib.h>
 #include <string.h>
 #include <stdio.h>
 #include <time.h>
+#include <unistd.h>
 #include "common.h"
 #include "server.h"
 #include "client.h"
 
 int free_mem_on_exit = 0;
+void *libpcap = NULL;
+
+void usage() {
+    puts("usage: udpintcp [OPTION]...\n"
+            "Make UDP look like TCP.\n"
+            "\n"
+            "  -m MODE                          Client/server mode.\n"
+            "  -h LISTEN_HOST -p LISTEN_PORT    Listen on the specified host/port. Port is required.\n"
+            "  -H REMOTE_HOST -P REMOTE_PORT    Connect to the specified host/port. Always required.\n"
+            "  -d DEVICE                        Use libpcap and listen on the specified interface.\n");
+}
 
 int main(int argc, char *argv[]) {
-    if (argc < 6) {
-        puts("usage: udpintcp client|server LISTEN_HOST LISTEN_PORT REMOTE_HOST REMOTE_PORT");
-        return !(argc == 2 && !strcmp(argv[1], "--help"));
+    char ch;
+    struct common_data common_data = {
+        .listen_host = "::"
+    };
+    const char *mode = NULL;
+    while ((ch = getopt(argc, argv, "m:h:p:H:P:d:")) != -1) {
+        switch (ch) {
+        case 'm':
+            mode = optarg;
+            break;
+        case 'h':
+            common_data.listen_host = optarg;
+            break;
+        case 'p':
+            common_data.listen_port = optarg;
+            break;
+        case 'H':
+            common_data.remote_host = optarg;
+            break;
+        case 'P':
+            common_data.remote_port = optarg;
+            break;
+        case 'd':
+            common_data.device = optarg;
+            break;
+        case '?':
+            usage();
+            break;
+        default:
+            abort();
+        }
+        if (optind > argc) {
+            fputs("extra arguments on command line\n", stderr);
+            exit(EXIT_FAILURE);
+        }
+    }
+    if (!mode) {
+        fputs("missing required argument: mode", stderr);
+        exit(EXIT_FAILURE);
+    }
+    if (!common_data.listen_port) {
+        fputs("missing required argument: listen port", stderr);
+        exit(EXIT_FAILURE);
+    }
+    if (!common_data.remote_host) {
+        fputs("missing required argument: remote host", stderr);
+        exit(EXIT_FAILURE);
+    }
+    if (!common_data.remote_port) {
+        fputs("missing required argument: remote port", stderr);
+        exit(EXIT_FAILURE);
     }
 
     srandom((unsigned int)time(NULL));
@@ -21,14 +82,17 @@ int main(int argc, char *argv[]) {
         free_mem_on_exit = 1;
     }
 
-    if (!strcmp(argv[1], "client")) {
-        DBG("starting client listening on [%s]:%s connecting to [%s]:%s", argv[2], argv[3], argv[4], argv[5]);
-        return start_client(argv[2], argv[3], argv[4], argv[5]) == 0;
-    } else if (!strcmp(argv[1], "server")) {
-        DBG("starting server listening on [%s]:%s connecting to [%s]:%s", argv[2], argv[3], argv[4], argv[5]);
-        return start_server(argv[2], argv[3], argv[4], argv[5]) == 0;
+    int (*startf)(struct common_data *);
+
+    if (!strcmp(mode, "client")) {
+        startf = start_client;
+    } else if (!strcmp(mode, "server")) {
+        startf = start_server;
     } else {
         fputs("invalid mode\n", stderr);
         return 1;
     }
+
+    DBG("starting %s listening on [%s]:%s connecting to [%s]:%s", mode, common_data.listen_host, common_data.listen_port, common_data.remote_host, common_data.remote_port);
+    return startf(&common_data);
 }