Clean up handling of the data before the Ethernet packet in ERF files.

The data before the Ethernet packet isn't a 16-bit little-endian
integer, it's two bytes, one byte of offset and one byte of padding.

Change-Id: I327b88f058dda184b79d3c2c6cf0dea52c0d28b1
Reviewed-on: https://code.wireshark.org/review/13254
Reviewed-by: Guy Harris <guy@alum.mit.edu>

5 files changed, 42 insertions, 29 deletions

diff --git a/epan/dissectors/packet-erf.c b/epan/dissectors/packet-erf.c
index 1d6075ae0f..8baf3888ff 100644
--- a/epan/dissectors/packet-erf.c
+++ b/epan/dissectors/packet-erf.c
@@ -41,11 +41,6 @@ void proto_reg_handoff_erf(void);
 #define EXT_HDR_TYPE_CHANNELISED    12
 #define EXT_HDR_TYPE_SIGNATURE      14
 
-struct erf_eth_hdrx {
-  guint8 byte0;
-  guint8 byte1;
-};
-
 #define DECHAN_MAX_LINE_RATE 5
 #define DECHAN_MAX_VC_SIZE 5
 #define DECHAN_MAX_AUG_INDEX 4
@@ -214,7 +209,7 @@ static int hf_erf_aal2_res1   = -1;
 /* ERF Ethernet header/pad */
 static int hf_erf_eth      = -1;
 static int hf_erf_eth_off  = -1;
-static int hf_erf_eth_res1 = -1;
+static int hf_erf_eth_pad  = -1;
 
 /* Initialize the subtree pointers */
 static gint ett_erf            = -1;
@@ -990,15 +985,16 @@ dissect_eth_header(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
   if (tree) {
     proto_item          *eth_item;
     proto_tree          *eth_tree;
-    struct erf_eth_hdrx *eth_hdr;
+    guint8               eth_offset, eth_pad;
 
     eth_item = proto_tree_add_item(tree, hf_erf_eth, tvb, 0, 0, ENC_NA);
 
     eth_tree = proto_item_add_subtree(eth_item, ett_erf_eth);
-    eth_hdr  = (struct erf_eth_hdrx *) (&pinfo->pseudo_header->erf.subhdr.eth_hdr);
+    eth_offset = pinfo->pseudo_header->erf.subhdr.eth_hdr.offset;
+    eth_pad = pinfo->pseudo_header->erf.subhdr.eth_hdr.pad;
 
-    proto_tree_add_uint(eth_tree, hf_erf_eth_off, tvb, 0, 0, eth_hdr->byte0);
-    proto_tree_add_uint(eth_tree, hf_erf_eth_res1, tvb, 0, 0, eth_hdr->byte1);
+    proto_tree_add_uint(eth_tree, hf_erf_eth_off, tvb, 0, 0, eth_offset);
+    proto_tree_add_uint(eth_tree, hf_erf_eth_pad, tvb, 0, 0, eth_pad);
   }
 }
 
@@ -1811,11 +1807,10 @@ proto_register_erf(void)
         FT_NONE, BASE_NONE, NULL, 0x0, NULL, HFILL } },
     { &hf_erf_eth_off,
       { "Offset", "erf.eth.off",
-        FT_UINT8, BASE_DEC, NULL, ETH_OFF_MASK, NULL, HFILL } },
-    { &hf_erf_eth_res1,
-      { "Reserved", "erf.eth.res1",
-        FT_UINT8, BASE_HEX, NULL, ETH_RES1_MASK, NULL, HFILL } },
-
+        FT_UINT8, BASE_DEC, NULL, 0x0, NULL, HFILL } },
+    { &hf_erf_eth_pad,
+      { "Padding", "erf.eth.pad",
+        FT_UINT8, BASE_HEX, NULL, 0x0, NULL, HFILL } },
   };
 
   static gint *ett[] = {
diff --git a/wiretap/erf.c b/wiretap/erf.c
index bb41f3c145..8daa0c3c9d 100644
--- a/wiretap/erf.c
+++ b/wiretap/erf.c
@@ -92,7 +92,7 @@ extern wtap_open_return_val erf_open(wtap *wth, int *err, gchar **err_info)
   erf_timestamp_t  prevts,ts;
   erf_header_t     header;
   guint32          mc_hdr;
-  guint16          eth_hdr;
+  struct erf_eth_hdr eth_hdr;
   guint32          packet_size;
   guint16          rlen;
   guint64          erf_ext_header;
@@ -338,12 +338,12 @@ static gboolean erf_read_header(FILE_T fh,
                                 guint32 *packet_size)
 {
   union wtap_pseudo_header *pseudo_header = &phdr->pseudo_header;
-  guint32 mc_hdr;
-  guint32 aal2_hdr;
   guint8  erf_exhdr[8];
   guint64 erf_exhdr_sw;
   guint8  type    = 0;
-  guint16 eth_hdr;
+  guint32 mc_hdr;
+  guint32 aal2_hdr;
+  struct wtap_erf_eth_hdr eth_hdr;
   guint32 skiplen = 0;
   int     i       = 0;
   int     max     = sizeof(pseudo_header->erf.ehdr_list)/sizeof(struct erf_ehdr);
@@ -454,7 +454,12 @@ static gboolean erf_read_header(FILE_T fh,
         *bytes_read += (guint32)sizeof(eth_hdr);
       *packet_size -=  (guint32)sizeof(eth_hdr);
       skiplen += (guint32)sizeof(eth_hdr);
-      pseudo_header->erf.subhdr.eth_hdr = g_ntohs(eth_hdr);
+      pseudo_header->erf.subhdr.eth_hdr = eth_hdr;
+      {
+      	guint8 bytes[2];
+      	memcpy(bytes, &eth_hdr, 2);
+      	fprintf(stderr, "offset %u, pad %u\n", bytes[0], bytes[1]);
+      }
       break;
 
     case ERF_TYPE_MC_HDLC:
@@ -526,8 +531,7 @@ static int wtap_wtap_encap_to_erf_encap(int encap)
 static gboolean erf_write_phdr(wtap_dumper *wdh, int encap, const union wtap_pseudo_header *pseudo_header, int * err)
 {
   guint8 erf_hdr[sizeof(struct erf_mc_phdr)];
-  guint8 erf_subhdr[((sizeof(struct erf_mc_hdr) > sizeof(struct erf_eth_hdr))?
-    sizeof(struct erf_mc_hdr) : sizeof(struct erf_eth_hdr))];
+  guint8 erf_subhdr[sizeof(union erf_subhdr)];
   guint8 ehdr[8*MAX_ERF_EHDR];
   size_t size        = 0;
   size_t subhdr_size = 0;
@@ -564,7 +568,7 @@ static gboolean erf_write_phdr(wtap_dumper *wdh, int encap, const union wtap_pse
         case ERF_TYPE_COLOR_ETH:
         case ERF_TYPE_DSM_COLOR_ETH:
         case ERF_TYPE_COLOR_HASH_ETH:
-          phtons(&erf_subhdr[0], pseudo_header->erf.subhdr.eth_hdr);
+          memcpy(&erf_subhdr[0], &pseudo_header->erf.subhdr.eth_hdr, sizeof pseudo_header->erf.subhdr.eth_hdr);
           subhdr_size += (int)sizeof(struct erf_eth_hdr);
           break;
         default:
diff --git a/wiretap/erf.h b/wiretap/erf.h
index 894235c7ad..870db96140 100644
--- a/wiretap/erf.h
+++ b/wiretap/erf.h
@@ -120,11 +120,13 @@ typedef struct erf_aal2_hdr {
 } erf_aal2_header_t;
 
 typedef struct erf_eth_hdr {
-	guint16	eth;
+	guint8 offset;
+	guint8 pad;
 } erf_eth_header_t;
 
 union erf_subhdr {
   struct erf_mc_hdr mc_hdr;
+  struct erf_aal2_hdr aal2_hdr;
   struct erf_eth_hdr eth_hdr;
 };
 
diff --git a/wiretap/pcap-common.c b/wiretap/pcap-common.c
index 02be511875..3df298f6f5 100644
--- a/wiretap/pcap-common.c
+++ b/wiretap/pcap-common.c
@@ -1485,7 +1485,6 @@ pcap_read_erf_subheader(FILE_T fh, union wtap_pseudo_header *pseudo_header,
 	case ERF_TYPE_MC_ATM:
 	case ERF_TYPE_MC_RAW_CHANNEL:
 	case ERF_TYPE_MC_AAL5:
-	case ERF_TYPE_MC_AAL2:
 	case ERF_TYPE_COLOR_MC_HDLC_POS:
 		/* Extract the Multi Channel header to include it in the pseudo header part */
 		if (!wtap_read_bytes(fh, erf_subhdr, sizeof(erf_mc_header_t), err, err_info))
@@ -1493,13 +1492,20 @@ pcap_read_erf_subheader(FILE_T fh, union wtap_pseudo_header *pseudo_header,
 		pseudo_header->erf.subhdr.mc_hdr = pntoh32(&erf_subhdr[0]);
 		*psize = sizeof(erf_mc_header_t);
 		break;
+	case ERF_TYPE_MC_AAL2:
+		/* Extract the AAL2 header to include it in the pseudo header part */
+		if (!wtap_read_bytes(fh, erf_subhdr, sizeof(erf_aal2_header_t), err, err_info))
+			return FALSE;
+		pseudo_header->erf.subhdr.aal2_hdr = pntoh32(&erf_subhdr[0]);
+		*psize = sizeof(erf_aal2_header_t);
+		break;
 	case ERF_TYPE_ETH:
 	case ERF_TYPE_COLOR_ETH:
 	case ERF_TYPE_DSM_COLOR_ETH:
 		/* Extract the Ethernet additional header to include it in the pseudo header part */
 		if (!wtap_read_bytes(fh, erf_subhdr, sizeof(erf_eth_header_t), err, err_info))
 			return FALSE;
-		pseudo_header->erf.subhdr.eth_hdr = pntoh16(&erf_subhdr[0]);
+		memcpy(&pseudo_header->erf.subhdr.eth_hdr, erf_subhdr, sizeof pseudo_header->erf.subhdr.eth_hdr);
 		*psize = sizeof(erf_eth_header_t);
 		break;
 	default:
@@ -2116,15 +2122,18 @@ pcap_write_phdr(wtap_dumper *wdh, int encap, const union wtap_pseudo_header *pse
 		case ERF_TYPE_MC_ATM:
 		case ERF_TYPE_MC_RAW_CHANNEL:
 		case ERF_TYPE_MC_AAL5:
-		case ERF_TYPE_MC_AAL2:
 		case ERF_TYPE_COLOR_MC_HDLC_POS:
 			phtonl(&erf_hdr[16], pseudo_header->erf.subhdr.mc_hdr);
 			size += (int)sizeof(struct erf_mc_hdr);
 			break;
+		case ERF_TYPE_MC_AAL2:
+			phtonl(&erf_hdr[16], pseudo_header->erf.subhdr.aal2_hdr);
+			size += (int)sizeof(struct erf_aal2_hdr);
+			break;
 		case ERF_TYPE_ETH:
 		case ERF_TYPE_COLOR_ETH:
 		case ERF_TYPE_DSM_COLOR_ETH:
-			phtons(&erf_hdr[16], pseudo_header->erf.subhdr.eth_hdr);
+			memcpy(&erf_hdr[16], &pseudo_header->erf.subhdr.eth_hdr, sizeof pseudo_header->erf.subhdr.eth_hdr);
 			size += (int)sizeof(struct erf_eth_hdr);
 			break;
 		default:
diff --git a/wiretap/wtap.h b/wiretap/wtap.h
index 39707abc15..c34547d491 100644
--- a/wiretap/wtap.h
+++ b/wiretap/wtap.h
@@ -938,7 +938,10 @@ struct erf_mc_phdr {
     struct erf_ehdr ehdr_list[MAX_ERF_EHDR];
     union
     {
-        guint16 eth_hdr;
+        struct wtap_erf_eth_hdr {
+            guint8 offset;
+            guint8 pad;
+        } eth_hdr;
         guint32 mc_hdr;
         guint32 aal2_hdr;
     } subhdr;