use master/worker to avoid unsolved coredump error

.travis.yml

@@ -0,0 +1,22 @@
+os:
+    - linux
+    - osx
+language: c
+compiler:
+    - gcc
+    - clang
+before_script:
+    - "mkdir -p m4"
+    - "autoreconf -if"
+script:
+    - "git clone https://github.com/sustrik/libmill.git"
+    - "pushd libmill"
+    - "./autogen.sh"
+    - "./configure"
+    - "make"
+    - "popd"
+    - "autoreconf -if"
+    - "export CPPFLAGS=-I$(pwd)/libmill"
+    - "export LDFLAGS=-L$(pwd)/libmill"
+    - "./configure --prefix=/usr --sysconfdir=/etc"
+    - "make"

configure.ac

@@ -33,7 +33,7 @@ AC_CHECK_LIB([mill], [go], [AC_SUBST(LIB_MILL)])
 
 # Checks for header files.
 AC_HEADER_ASSERT
-AC_CHECK_HEADERS([fcntl.h libmill.h limits.h netdb.h pwd.h stddef.h stdint.h stdio.h stdlib.h string.h sys/ioctl.h sys/socket.h sys/stat.h sys/time.h unistd.h])
+AC_CHECK_HEADERS([fcntl.h libmill.h limits.h netdb.h pwd.h stddef.h stdint.h stdio.h stdlib.h string.h sys/ioctl.h sys/socket.h sys/stat.h sys/time.h sys/wait.h unistd.h])
 
 # Check build target
 case "$host" in

src/main.c

@@ -21,18 +21,27 @@
 #include <signal.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <sys/wait.h>
+#include <unistd.h>
 #include "conf.h"
+#include "log.h"
 #include "utils.h"
 #include "vpn.h"
 
 #ifdef HAVE_CONFIG_H
 #  include "config.h"
 #endif
 
+// role == 0 -> master, role == 1 -> worker
+static int role;
+
 static void signal_cb(int signo)
 {
     (void)signo;
-    vpn_stop();
+    if (role == 1)
+    {
+        vpn_stop();
+    }
 }
 
 int main(int argc, char **argv)
@@ -73,5 +82,33 @@ int main(int argc, char **argv)
         return EXIT_FAILURE;
     }
 
-    return vpn_run();
+    while (1)
+    {
+        int cpid = fork();
+        if (cpid < 0)
+        {
+            LOG("failed to spawn worker process");
+        }
+        else if (cpid == 0)
+        {
+            // worker
+            role = 1;
+            vpn_run();
+            return 0;
+        }
+        else
+        {
+            // master
+            int status;
+            wait(&status);
+            if (WIFEXITED(status))
+            {
+                return 0;
+            }
+            else
+            {
+                LOG("worker terminated unexpectedly, respawn woker");
+            }
+        }
+    }
 }

src/vpn.c

@@ -329,7 +329,6 @@ coroutine static void udp_worker(int port, int timeout)
         }
 
         // 写入到 tun 设备
-        assert(pbuf.len < sizeof(pbuf.payload));
         n = tun_write(tun, pbuf.payload, pbuf.len);
         if (n < 0)
         {
@@ -465,7 +464,6 @@ static int encapsulate(pbuf_t *pbuf)
 
     // 加密
     ssize_t n = PAYLOAD_OFFSET + pbuf->len + pbuf->padding;
-    assert(n < (ssize_t)sizeof(pbuf->payload));
     crypto_encrypt(pbuf);
 
     return (int)n;
@@ -476,7 +474,7 @@ static int encapsulate(pbuf_t *pbuf)
 static int decapsulate(pbuf_t *pbuf, int n)
 {
     assert(pbuf != NULL);
-    assert(n < (int)sizeof(pbuf->payload));
+    assert(n <= (int)conf->mtu + PAYLOAD_OFFSET);
 
     // 解密
     int invalid = crypto_decrypt(pbuf, n);
@@ -511,7 +509,7 @@ static int decapsulate(pbuf_t *pbuf, int n)
         // 暂不处理 ack flag
     }
 
-    assert(pbuf->len < sizeof(pbuf->payload));
+    assert(pbuf->len <= conf->mtu);
     return (int)(pbuf->len);
 }