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code cosmetics: clean up some if() chains and replace by switch() statements

This commit is contained in:
hannes 2006-02-22 10:38:28 +00:00
parent 525e3cbe8f
commit b1a31d31cc
1 changed files with 148 additions and 153 deletions
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301
gencode.c
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@ -21,7 +21,7 @@
*/
#ifndef lint
static const char rcsid[] _U_ =
"@(#) $Header: /tcpdump/master/libpcap/gencode.c,v 1.263 2006-02-22 10:22:04 hannes Exp $ (LBL)";
"@(#) $Header: /tcpdump/master/libpcap/gencode.c,v 1.264 2006-02-22 10:38:28 hannes Exp $ (LBL)";
#endif
#ifdef HAVE_CONFIG_H
@ -5862,154 +5862,146 @@ gen_multicast(proto)
case Q_DEFAULT:
case Q_LINK:
if (linktype == DLT_ARCNET || linktype == DLT_ARCNET_LINUX)
/* all ARCnet multicasts use the same address */
return gen_ahostop(abroadcast, Q_DST);
if (linktype == DLT_EN10MB) {
/* ether[0] & 1 != 0 */
return gen_mac_multicast(0);
}
if (linktype == DLT_FDDI) {
/*
* XXX TEST THIS: MIGHT NOT PORT PROPERLY XXX
*
* XXX - was that referring to bit-order issues?
*/
/* fddi[1] & 1 != 0 */
return gen_mac_multicast(1);
}
if (linktype == DLT_IEEE802) {
/* tr[2] & 1 != 0 */
return gen_mac_multicast(2);
}
if (linktype == DLT_IEEE802_11 ||
linktype == DLT_IEEE802_11_RADIO_AVS ||
linktype == DLT_IEEE802_11_RADIO ||
linktype == DLT_PRISM_HEADER) {
/*
* Oh, yuk.
*
* For control frames, there is no DA.
*
* For management frames, DA is at an
* offset of 4 from the beginning of
* the packet.
*
* For data frames, DA is at an offset
* of 4 from the beginning of the packet
* if To DS is clear and at an offset of
* 16 from the beginning of the packet
* if To DS is set.
*/
/*
* Generate the tests to be done for data frames.
*
* First, check for To DS set, i.e. "link[1] & 0x01".
*/
s = gen_load_a(OR_LINK, 1, BPF_B);
b1 = new_block(JMP(BPF_JSET));
b1->s.k = 0x01; /* To DS */
b1->stmts = s;
/*
* If To DS is set, the DA is at 16.
*/
b0 = gen_mac_multicast(16);
gen_and(b1, b0);
/*
* Now, check for To DS not set, i.e. check
* "!(link[1] & 0x01)".
*/
s = gen_load_a(OR_LINK, 1, BPF_B);
b2 = new_block(JMP(BPF_JSET));
b2->s.k = 0x01; /* To DS */
b2->stmts = s;
gen_not(b2);
/*
* If To DS is not set, the DA is at 4.
*/
b1 = gen_mac_multicast(4);
gen_and(b2, b1);
/*
* Now OR together the last two checks. That gives
* the complete set of checks for data frames.
*/
gen_or(b1, b0);
/*
* Now check for a data frame.
* I.e, check "link[0] & 0x08".
*/
s = gen_load_a(OR_LINK, 0, BPF_B);
b1 = new_block(JMP(BPF_JSET));
b1->s.k = 0x08;
b1->stmts = s;
/*
* AND that with the checks done for data frames.
*/
gen_and(b1, b0);
/*
* If the high-order bit of the type value is 0, this
* is a management frame.
* I.e, check "!(link[0] & 0x08)".
*/
s = gen_load_a(OR_LINK, 0, BPF_B);
b2 = new_block(JMP(BPF_JSET));
b2->s.k = 0x08;
b2->stmts = s;
gen_not(b2);
/*
* For management frames, the DA is at 4.
*/
b1 = gen_mac_multicast(4);
gen_and(b2, b1);
/*
* OR that with the checks done for data frames.
* That gives the checks done for management and
* data frames.
*/
gen_or(b1, b0);
/*
* If the low-order bit of the type value is 1,
* this is either a control frame or a frame
* with a reserved type, and thus not a
* frame with an SA.
*
* I.e., check "!(link[0] & 0x04)".
*/
s = gen_load_a(OR_LINK, 0, BPF_B);
b1 = new_block(JMP(BPF_JSET));
b1->s.k = 0x04;
b1->stmts = s;
gen_not(b1);
/*
* AND that with the checks for data and management
* frames.
*/
gen_and(b1, b0);
return b0;
}
if (linktype == DLT_IP_OVER_FC) {
b0 = gen_mac_multicast(2);
return b0;
}
if (linktype == DLT_SUNATM && is_lane) {
switch (linktype) {
case DLT_ARCNET:
case DLT_ARCNET_LINUX:
/* all ARCnet multicasts use the same address */
return gen_ahostop(abroadcast, Q_DST);
case DLT_EN10MB:
/* ether[0] & 1 != 0 */
return gen_mac_multicast(0);
case DLT_FDDI:
/*
* XXX TEST THIS: MIGHT NOT PORT PROPERLY XXX
*
* XXX - was that referring to bit-order issues?
*/
/* fddi[1] & 1 != 0 */
return gen_mac_multicast(1);
case DLT_IEEE802:
/* tr[2] & 1 != 0 */
return gen_mac_multicast(2);
case DLT_IEEE802_11:
case DLT_IEEE802_11_RADIO_AVS:
case DLT_IEEE802_11_RADIO:
case DLT_PRISM_HEADER:
/*
* Oh, yuk.
*
* For control frames, there is no DA.
*
* For management frames, DA is at an
* offset of 4 from the beginning of
* the packet.
*
* For data frames, DA is at an offset
* of 4 from the beginning of the packet
* if To DS is clear and at an offset of
* 16 from the beginning of the packet
* if To DS is set.
*/
/*
* Generate the tests to be done for data frames.
*
* First, check for To DS set, i.e. "link[1] & 0x01".
*/
s = gen_load_a(OR_LINK, 1, BPF_B);
b1 = new_block(JMP(BPF_JSET));
b1->s.k = 0x01; /* To DS */
b1->stmts = s;
/*
* If To DS is set, the DA is at 16.
*/
b0 = gen_mac_multicast(16);
gen_and(b1, b0);
/*
* Now, check for To DS not set, i.e. check
* "!(link[1] & 0x01)".
*/
s = gen_load_a(OR_LINK, 1, BPF_B);
b2 = new_block(JMP(BPF_JSET));
b2->s.k = 0x01; /* To DS */
b2->stmts = s;
gen_not(b2);
/*
* If To DS is not set, the DA is at 4.
*/
b1 = gen_mac_multicast(4);
gen_and(b2, b1);
/*
* Now OR together the last two checks. That gives
* the complete set of checks for data frames.
*/
gen_or(b1, b0);
/*
* Now check for a data frame.
* I.e, check "link[0] & 0x08".
*/
s = gen_load_a(OR_LINK, 0, BPF_B);
b1 = new_block(JMP(BPF_JSET));
b1->s.k = 0x08;
b1->stmts = s;
/*
* AND that with the checks done for data frames.
*/
gen_and(b1, b0);
/*
* If the high-order bit of the type value is 0, this
* is a management frame.
* I.e, check "!(link[0] & 0x08)".
*/
s = gen_load_a(OR_LINK, 0, BPF_B);
b2 = new_block(JMP(BPF_JSET));
b2->s.k = 0x08;
b2->stmts = s;
gen_not(b2);
/*
* For management frames, the DA is at 4.
*/
b1 = gen_mac_multicast(4);
gen_and(b2, b1);
/*
* OR that with the checks done for data frames.
* That gives the checks done for management and
* data frames.
*/
gen_or(b1, b0);
/*
* If the low-order bit of the type value is 1,
* this is either a control frame or a frame
* with a reserved type, and thus not a
* frame with an SA.
*
* I.e., check "!(link[0] & 0x04)".
*/
s = gen_load_a(OR_LINK, 0, BPF_B);
b1 = new_block(JMP(BPF_JSET));
b1->s.k = 0x04;
b1->stmts = s;
gen_not(b1);
/*
* AND that with the checks for data and management
* frames.
*/
gen_and(b1, b0);
return b0;
case DLT_IP_OVER_FC:
b0 = gen_mac_multicast(2);
return b0;
case DLT_SUNATM:
if (is_lane) {
/*
* Check that the packet doesn't begin with an
* LE Control marker. (We've already generated
@ -6023,10 +6015,13 @@ gen_multicast(proto)
b0 = gen_mac_multicast(off_mac);
gen_and(b1, b0);
return b0;
}
/* Link not known to support multicasts */
break;
}
break;
default:
break;
}
/* Link not known to support multicasts */
break;
case Q_IP:
b0 = gen_linktype(ETHERTYPE_IP);