From 06553e55d6ff2b203c4ab1dda2d6fb15c45e2896 Mon Sep 17 00:00:00 2001
From: Guy Harris <guy@alum.mit.edu>
Date: Wed, 5 Nov 2014 14:33:14 -0800
Subject: [PATCH 5/5] Move the socket ops out of gencode.c.
Instead, do it in pcap-linux.c, and have it set a flag in the pcap_t
structure to indicate to the code in gencode.c that it needs to generate
special VLAN-handling code.
(cherry picked from 612503bb0801a49a1c6ebe9c82591289b1d2e5c9)
Conflicts:
pcap-linux.c
---
gencode.c | 37 ++++++++++++++-----------------------
pcap-int.h | 10 ++++++++++
pcap-linux.c | 24 ++++++++++++++++++++++++
pcap.c | 12 ++++++++++++
savefile.c | 5 +++++
5 files changed, 65 insertions(+), 23 deletions(-)
diff --git a/gencode.c b/gencode.c
index 9c1d17b..6b3772f 100644
--- a/gencode.c
+++ b/gencode.c
@@ -58,7 +58,6 @@ static const char rcsid[] _U_ =
#include <netinet/in.h>
#include <arpa/inet.h>
-#include <errno.h>
#endif /* WIN32 */
@@ -7864,23 +7863,11 @@ gen_ahostop(eaddr, dir)
}
#if defined(SKF_AD_VLAN_TAG) && defined(SKF_AD_VLAN_TAG_PRESENT)
-static int skf_ad_vlan_tag_present_supported(int bpf_extensions) {
- return bpf_extensions >= SKF_AD_VLAN_TAG_PRESENT;
-}
-
static struct block *
-gen_vlan_bpf_extensions(int vlan_num) {
+gen_vlan_bpf_extensions(int vlan_num)
+{
struct block *b0, *b1;
struct slist *s;
- int val = 0, len, r;
-
- len = sizeof(val);
- r = getsockopt(bpf_pcap->fd, SOL_SOCKET, SO_BPF_EXTENSIONS, &val, &len);
- if (r < 0)
- return NULL;
-
- if (!skf_ad_vlan_tag_present_supported(val))
- return NULL;
/* generate new filter code based on extracting packet
* metadata */
@@ -7908,7 +7895,8 @@ gen_vlan_bpf_extensions(int vlan_num) {
#endif
static struct block *
-gen_vlan_no_bpf_extensions(int vlan_num) {
+gen_vlan_no_bpf_extensions(int vlan_num)
+{
struct block *b0, *b1;
/* check for VLAN, including QinQ */
@@ -7985,14 +7973,17 @@ gen_vlan(vlan_num)
case DLT_NETANALYZER:
case DLT_NETANALYZER_TRANSPARENT:
#if defined(SKF_AD_VLAN_TAG) && defined(SKF_AD_VLAN_TAG_PRESENT)
- if (!vlan_stack_depth) {
- b0 = gen_vlan_bpf_extensions(vlan_num);
- if (!b0)
- b0 = gen_vlan_no_bpf_extensions(vlan_num);
- }
- else
+ if (vlan_stack_depth == 0) {
+ /*
+ * Do we need special VLAN handling?
+ */
+ if (bpf_pcap->bpf_codegen_flags & BPF_SPECIAL_VLAN_HANDLING)
+ b0 = gen_vlan_bpf_extensions(vlan_num);
+ else
+ b0 = gen_vlan_no_bpf_extensions(vlan_num);
+ } else
#endif
- b0 = gen_vlan_no_bpf_extensions(vlan_num);
+ b0 = gen_vlan_no_bpf_extensions(vlan_num);
break;
default:
bpf_error("no VLAN support for data link type %d",
diff --git a/pcap-int.h b/pcap-int.h
index 0c27ec7..c9dbb5f 100644
--- a/pcap-int.h
+++ b/pcap-int.h
@@ -182,6 +182,11 @@ struct pcap {
pcap_direction_t direction;
/*
+ * Flags to affect BPF code generation.
+ */
+ int bpf_codegen_flags;
+
+ /*
* Placeholder for filter code if bpf not in kernel.
*/
struct bpf_program fcode;
@@ -228,6 +233,11 @@ struct pcap {
};
/*
+ * BPF code generation flags.
+ */
+#define BPF_SPECIAL_VLAN_HANDLING 0x00000001 /* special VLAN handling for Linux */
+
+/*
* This is a timeval as stored in a savefile.
* It has to use the same types everywhere, independent of the actual
* `struct timeval'; `struct timeval' has 32-bit tv_sec values on some
diff --git a/pcap-linux.c b/pcap-linux.c
index a370858..a82f4eb 100644
--- a/pcap-linux.c
+++ b/pcap-linux.c
@@ -3024,6 +3024,10 @@ activate_new(pcap_t *handle)
#endif
int err = 0;
struct packet_mreq mr;
+#ifdef SO_BPF_EXTENSIONS
+ int bpf_extensions;
+ socklen_t len;
+#endif
/*
* Open a socket with protocol family packet. If the
@@ -3342,6 +3346,26 @@ activate_new(pcap_t *handle)
/* Save the socket FD in the pcap structure */
handle->fd = sock_fd;
+#ifdef SO_BPF_EXTENSIONS
+ /*
+ * Can we generate special code for VLAN checks?
+ * (XXX - what if we need the special code but it's not supported
+ * by the OS? Is that possible?)
+ */
+ len = sizeof(bpf_extensions);
+
+ if (getsockopt(sock_fd, SOL_SOCKET, SO_BPF_EXTENSIONS, &bpf_extensions, &len) == 0) {
+ if (bpf_extensions >= SKF_AD_VLAN_TAG_PRESENT) {
+ /*
+ * Yes, we can. Request that we do so.
+ */
+ handle->bpf_codegen_flags |= BPF_SPECIAL_VLAN_HANDLING;
+ }
+ }
+#endif /* SO_BPF_EXTENSIONS */
+
+
+
#if defined(SIOCGSTAMPNS) && defined(SO_TIMESTAMPNS)
if (handle->opt.tstamp_precision == PCAP_TSTAMP_PRECISION_NANO) {
int nsec_tstamps = 1;
diff --git a/pcap.c b/pcap.c
index 6b16cea..74dc708 100644
--- a/pcap.c
+++ b/pcap.c
@@ -558,6 +558,12 @@ pcap_create_common(const char *source, char *ebuf, size_t size)
p->opt.immediate = 0;
p->opt.tstamp_type = -1; /* default to not setting time stamp type */
p->opt.tstamp_precision = PCAP_TSTAMP_PRECISION_MICRO;
+
+ /*
+ * Start out with no BPF code generation flags set.
+ */
+ p->bpf_codegen_flags = 0;
+
return (p);
}
@@ -1810,6 +1816,12 @@ pcap_open_dead_with_tstamp_precision(int linktype, int snaplen, u_int precision)
p->setmintocopy_op = pcap_setmintocopy_dead;
#endif
p->cleanup_op = pcap_cleanup_dead;
+
+ /*
+ * A "dead" pcap_t never requires special BPF code generation.
+ */
+ p->bpf_codegen_flags = 0;
+
p->activated = 1;
return (p);
}
diff --git a/savefile.c b/savefile.c
index 73e3ea9..98f9c82 100644
--- a/savefile.c
+++ b/savefile.c
@@ -349,6 +349,11 @@ found:
*/
p->oneshot_callback = pcap_oneshot;
+ /*
+ * Savefiles never require special BPF code generation.
+ */
+ p->bpf_codegen_flags = 0;
+
p->activated = 1;
return (p);
--
2.4.3