Work around annoying Android problem.

For various annoying reasons having to do with DHCP software, some
versions of Android give the mobile-phone-network interface an ARPHRD_
value of ARPHRD_ETHER, even though the packet supplied by that interface
have no link-layer header, and begin with an IP header, so that the
ARPHRD_ value should be ARPHRD_NONE.

Detect those devices by checking the device name, and use DLT_RAW for them.

diff --git a/pcap-linux.c b/pcap-linux.c
index 6fb2be1cd8b8d6d3d22bcb279a384a55dbe9e909..32f5be663cd9bd4afb27a06ae43beaf22cea5f00 100644 (file)
--- a/pcap-linux.c
+++ b/pcap-linux.c
@@ -318,7 +318,7 @@ typedef int         socklen_t;
 /*
  * Prototypes for internal functions and methods.
  */
-static void map_arphrd_to_dlt(pcap_t *, int, int);
+static void map_arphrd_to_dlt(pcap_t *, int, const char *, int);
 #ifdef HAVE_PF_PACKET_SOCKETS
 static short int map_packet_type_to_sll_type(short int);
 #endif
@@ -2605,11 +2605,31 @@ map_packet_type_to_sll_type(short int sll_pkttype)
  *
  *  Sets the link type to -1 if unable to map the type.
  */
-static void map_arphrd_to_dlt(pcap_t *handle, int arptype, int cooked_ok)
+static void map_arphrd_to_dlt(pcap_t *handle, int arptype, const char *device,
+                             int cooked_ok)
 {
+       static const char cdma_rmnet[] = "cdma_rmnet";
+
        switch (arptype) {
 
        case ARPHRD_ETHER:
+               /*
+                * For various annoying reasons having to do with DHCP
+                * software, some versions of Android give the mobile-
+                * phone-network interface an ARPHRD_ value of
+                * ARPHRD_ETHER, even though the packet supplied by
+                * that interface have no link-layer header, and begin
+                * with an IP header, so that the ARPHRD_ value should
+                * be ARPHRD_NONE.
+                *
+                * Detect those devices by checking the device name, and
+                * use DLT_RAW for them.
+                */
+               if (strncmp(device, cdma_rmnet, sizeof cdma_rmnet - 1) == 0) {
+                       handle->linktype = DLT_RAW;
+                       return;
+               }
+       
                /*
                 * This is (presumably) a real Ethernet capture; give it a
                 * link-layer-type list with DLT_EN10MB and DLT_DOCSIS, so
@@ -3035,7 +3055,7 @@ activate_new(pcap_t *handle)
                        close(sock_fd);
                        return arptype;
                }
-               map_arphrd_to_dlt(handle, arptype, 1);
+               map_arphrd_to_dlt(handle, arptype, device, 1);
                if (handle->linktype == -1 ||
                    handle->linktype == DLT_LINUX_SLL ||
                    handle->linktype == DLT_LINUX_IRDA ||
@@ -5152,7 +5172,7 @@ activate_old(pcap_t *handle)
         * Try to find the DLT_ type corresponding to that
         * link-layer type.
         */
-       map_arphrd_to_dlt(handle, arptype, 0);
+       map_arphrd_to_dlt(handle, arptype, device, 0);
        if (handle->linktype == -1) {
                snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
                         "unknown arptype %d", arptype);