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libpcap
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Fixed the code that verifies if a PPI packet encapsulates 802.11 frames. 

The bug was causing side effects even when the linktype was not PPI.
This commit is contained in:
gianluca 2007-06-14 20:54:12 +00:00
parent f6f11bf248
commit 88cba4849d
1 changed files with 33 additions and 11 deletions
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44
gencode.c
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@ -21,7 +21,7 @@
*/
#ifndef lint
static const char rcsid[] _U_ =
"@(#) $Header: /tcpdump/master/libpcap/gencode.c,v 1.221.2.50 2007-06-14 18:42:43 gianluca Exp $ (LBL)";
"@(#) $Header: /tcpdump/master/libpcap/gencode.c,v 1.221.2.51 2007-06-14 20:54:12 gianluca Exp $ (LBL)";
#endif
#ifdef HAVE_CONFIG_H
@ -243,6 +243,7 @@ static struct slist *xfer_to_a(struct arth *);
static struct block *gen_mac_multicast(int);
static struct block *gen_len(int, int);
static struct block *gen_ppi_dlt_check();
static struct block *gen_msg_abbrev(int type);
static void *
@ -478,11 +479,20 @@ merge(b0, b1)
*p = b1;
}
void
finish_parse(p)
struct block *p;
{
insert_load_llprefixlen(p);
struct block *ppi_dlt_check;
ppi_dlt_check = gen_ppi_dlt_check();
if (ppi_dlt_check != NULL)
{
gen_and(ppi_dlt_check, p);
}
backpatch(p, gen_retblk(snaplen));
p->sense = !p->sense;
backpatch(p, gen_retblk(0));
@ -503,6 +513,8 @@ finish_parse(p)
* require the length of that header, doing more for that
* header length isn't really worth the effort.
*/
insert_load_llprefixlen(root);
}
void
@ -1908,9 +1920,6 @@ insert_ppi_load_llprefixlen(b)
struct block *b;
{
struct slist *s1, *s2;
struct slist *s_load_dlt;
struct block *new_b;
struct block temp;
/*
* Prepend to the statements in this block code to load the
@ -1968,20 +1977,33 @@ insert_ppi_load_llprefixlen(b)
sappend(s1, b->stmts);
b->stmts = s1;
temp = *b;
}
}
static struct block *
gen_ppi_dlt_check()
{
struct slist *s_load_dlt;
struct block *b;
if (linktype == DLT_PPI)
{
/* Create the statements that check for the DLT
*/
s_load_dlt = new_stmt(BPF_LD|BPF_W|BPF_ABS);
s_load_dlt->s.k = 4;
new_b = new_block(JMP(BPF_JEQ));
b = new_block(JMP(BPF_JEQ));
new_b->stmts = s_load_dlt;
new_b->s.k = SWAPLONG(DLT_IEEE802_11);
gen_and(new_b,b);
b->stmts = s_load_dlt;
b->s.k = SWAPLONG(DLT_IEEE802_11);
}
else
{
b = NULL;
}
return b;
}
static void