Changeset f0c639b for lib

Timestamp:

03/26/07 11:47:31 (15 years ago)

Author:

Scott Raynel <smr26@…>

Branches:

4.0.1-hotfixes, cachetimestamps, develop, dpdk-ndag, etsilive, getfragoff, help, libtrace4, master, ndag_format, pfring, rc-4.0.1, rc-4.0.2, rc-4.0.3, rc-4.0.4, ringdecrementfix, ringperformance, ringtimestampfixes

Children:

38f9537

Parents:

be22b51

Message:

• Remove trace_get_wireless_fcs as it is no longer part of the Radiotap standard.
• Update trace_get_wire_length to account for the presence (or absence) of FCS bytes at the end of wireless frames. (only pcap and pcapfile for now)
• Update radiotap libpacketdump decoder to no longer output non-standard FCS field.
• Update test-wireless to ensure new length functions work correctly.

Location:

lib

Files:

• format_pcap.c (modified) (1 diff)
• format_pcapfile.c (modified) (1 diff)
• libtrace.h.in (modified) (2 diffs)
• libtrace_int.h (modified) (1 diff)
• link_wireless.c (modified) (3 diffs)

lib/format_pcap.c

@@ -513 +513 @@
         if (packet->type==pcap_dlt_to_rt(TRACE_DLT_EN10MB))
                 return pcapptr->len+4; /* Include the missing FCS */
-        else
-                return pcapptr->len;
+        else if (packet->type==pcap_dlt_to_rt(TRACE_DLT_IEEE802_11_RADIO)) {
+                /* If the packet is Radiotap and the flags field indicates
+                 * that the FCS is not included in the 802.11 frame, then
+                 * we need to add 4 to the wire-length to account for it.
+                 */
+                uint16_t flags;
+                trace_get_wireless_flags(trace_get_link(packet), trace_get_link_type(packet), &flags);
+                if ((flags & TRACE_RADIOTAP_F_FCS) == 0)
+                        return pcapptr->len + 4;
+        }
+        return pcapptr->len;
 }
 

lib/format_pcapfile.c

@@ -432 +432 @@
                 /* Include the missing FCS */
                 return swapl(packet->trace,pcapptr->wirelen)+4; 
-        else
-                return swapl(packet->trace,pcapptr->wirelen);
+        else if (packet->type==pcap_dlt_to_rt(TRACE_DLT_IEEE802_11_RADIO)) {
+                /* If the packet is Radiotap and the flags field indicates
+                 * that the FCS is not included in the 802.11 frame, then
+                 * we need to add 4 to the wire-length to account for it.
+                 */
+                uint16_t flags;
+                trace_get_wireless_flags(trace_get_link(packet), trace_get_link_type(packet), &flags);
+                if ((flags & TRACE_RADIOTAP_F_FCS) == 0)
+                        return swapl(packet->trace,pcapptr->wirelen)+4;
+        }
+        return swapl(packet->trace,pcapptr->wirelen);
 }
 

lib/libtrace.h.in

@@ -347 +347 @@
     TRACE_RADIOTAP_DB_ANTSIGNAL = 12, /**< Signal power in dB from a fixed reference (uint8) */
     TRACE_RADIOTAP_DB_ANTNOISE = 13, /**< Noise power in dB from a fixed reference (uint8) */
-    TRACE_RADIOTAP_FCS = 14, /**< Received frame check sequence (uint32) */
     TRACE_RADIOTAP_EXT = 31
 } libtrace_radiotap_field_t;
@@ -1625 +1624 @@
         libtrace_linktype_t linktype, uint8_t *antenna);
 
-/** Get the wireless Frame Check Sequence field
- * @param link the wireless header
- * @param linktype the linktype of the wireless header passed in
- * @param[out] fcs the Frame Check Sequence of the frame. 
- * @return true if the field was available, false if not.
- */
-DLLEXPORT bool trace_get_wireless_fcs(void *linkptr,
-        libtrace_linktype_t linktype, uint32_t *fcs);
-
 /*@}*/
 

lib/libtrace_int.h

@@ -457 +457 @@
 void duck_constructor(void);
 
-
+/* Used internally by get_wire_length() methods */
+bool trace_get_wireless_flags(void *link, libtrace_linktype_t linktype, uint8_t *flags);
+#define TRACE_RADIOTAP_F_FCS 0x10
         
 #ifdef __cplusplus

lib/link_wireless.c

@@ -156 +156 @@
         if (field == TRACE_RADIOTAP_DB_ANTNOISE)
                 return (void *) p;
+        /*
         if (bswap_le_to_host32(rtap->it_present) & (1 << TRACE_RADIOTAP_DB_ANTNOISE))
                 p+= sizeof (uint8_t);
-
-        if (field == TRACE_RADIOTAP_FCS)
-                ALIGN_NATURAL_32(p,s);
-        return (void *)p;
+        */
 
         /* Unknown field */
@@ -198 +196 @@
  * for now. Maybe it will be included in the API later if it becomes useful
  * and we come up with a suitable abstraction.
- */
-static
+ * This function isn't marked static as the various format modules need to
+ * access it for get_wire_length(). It's not meant to be exported though.
+ */
 bool trace_get_wireless_flags(void *link, 
                 libtrace_linktype_t linktype, uint8_t *flags)
@@ -591 +590 @@
 }
 
-DLLEXPORT bool trace_get_wireless_fcs(void *link,
-                libtrace_linktype_t linktype, uint32_t *fcs)
-{
-        uint32_t *p;
-        void *l;
-        uint16_t type;
-
-        if (link == NULL || fcs == NULL) return false;
-        switch (linktype) {
-                case TRACE_TYPE_80211_RADIO:
-                        if ((p = (uint32_t *) trace_get_radiotap_field(link,
-                                                        TRACE_RADIOTAP_FCS))) {
-                                *fcs = bswap_le_to_host32(*p);
-                                return true;
-                        } else break;
-                case TRACE_TYPE_LINUX_SLL:
-                        l = trace_get_payload_from_linux_sll(link, &type, NULL);
-                        return trace_get_wireless_fcs(l, arphrd_type_to_libtrace(type), fcs);
-                default:
-                        return false;
-        }
-        return false;
-}
-