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[NETFILTER]: ip_nat_snmp_basic annotations.

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... and switch the damn checksum update to something saner

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Al Viro 2006-11-20 18:06:59 -08:00 committed by David S. Miller
parent 8e5200f540
commit 5b14027bf2
1 changed files with 34 additions and 51 deletions
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85
net/ipv4/netfilter/ip_nat_snmp_basic.c
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@ -64,7 +64,7 @@ MODULE_DESCRIPTION("Basic SNMP Application Layer Gateway");
#define SNMP_PORT 161
#define SNMP_TRAP_PORT 162
#define NOCT1(n) (u_int8_t )((n) & 0xff)
#define NOCT1(n) (*(u8 *)n)
static int debug;
static DEFINE_SPINLOCK(snmp_lock);
@ -613,7 +613,7 @@ struct snmp_v1_trap
static inline void mangle_address(unsigned char *begin,
unsigned char *addr,
const struct oct1_map *map,
u_int16_t *check);
__sum16 *check);
struct snmp_cnv
{
unsigned int class;
@ -873,38 +873,24 @@ static unsigned char snmp_request_decode(struct asn1_ctx *ctx,
* Fast checksum update for possibly oddly-aligned UDP byte, from the
* code example in the draft.
*/
static void fast_csum(unsigned char *csum,
static void fast_csum(__sum16 *csum,
const unsigned char *optr,
const unsigned char *nptr,
int odd)
int offset)
{
long x, old, new;
x = csum[0] * 256 + csum[1];
x =~ x & 0xFFFF;
if (odd) old = optr[0] * 256;
else old = optr[0];
x -= old & 0xFFFF;
if (x <= 0) {
x--;
x &= 0xFFFF;
unsigned char s[4];
if (offset & 1) {
s[0] = s[2] = 0;
s[1] = ~*optr;
s[3] = *nptr;
} else {
s[1] = s[3] = 0;
s[0] = ~*optr;
s[2] = *nptr;
}
if (odd) new = nptr[0] * 256;
else new = nptr[0];
x += new & 0xFFFF;
if (x & 0x10000) {
x++;
x &= 0xFFFF;
}
x =~ x & 0xFFFF;
csum[0] = x / 256;
csum[1] = x & 0xFF;
*csum = csum_fold(csum_partial(s, 4, ~csum_unfold(*csum)));
}
/*
@ -915,9 +901,9 @@ static void fast_csum(unsigned char *csum,
static inline void mangle_address(unsigned char *begin,
unsigned char *addr,
const struct oct1_map *map,
u_int16_t *check)
__sum16 *check)
{
if (map->from == NOCT1(*addr)) {
if (map->from == NOCT1(addr)) {
u_int32_t old;
if (debug)
@ -927,11 +913,8 @@ static inline void mangle_address(unsigned char *begin,
/* Update UDP checksum if being used */
if (*check) {
unsigned char odd = !((addr - begin) % 2);
fast_csum((unsigned char *)check,
&map->from, &map->to, odd);
fast_csum(check,
&map->from, &map->to, addr - begin);
}
if (debug)
@ -943,7 +926,7 @@ static inline void mangle_address(unsigned char *begin,
static unsigned char snmp_trap_decode(struct asn1_ctx *ctx,
struct snmp_v1_trap *trap,
const struct oct1_map *map,
u_int16_t *check)
__sum16 *check)
{
unsigned int cls, con, tag, len;
unsigned char *end;
@ -1037,7 +1020,7 @@ static void hex_dump(unsigned char *buf, size_t len)
static int snmp_parse_mangle(unsigned char *msg,
u_int16_t len,
const struct oct1_map *map,
u_int16_t *check)
__sum16 *check)
{
unsigned char *eoc, *end;
unsigned int cls, con, tag, vers, pdutype;
@ -1223,12 +1206,12 @@ static int snmp_translate(struct ip_conntrack *ct,
*/
if (dir == IP_CT_DIR_ORIGINAL) {
/* SNAT traps */
map.from = NOCT1(ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.ip);
map.to = NOCT1(ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.ip);
map.from = NOCT1(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.ip);
map.to = NOCT1(&ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.ip);
} else {
/* DNAT replies */
map.from = NOCT1(ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.ip);
map.to = NOCT1(ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.ip);
map.from = NOCT1(&ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.ip);
map.to = NOCT1(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.ip);
}
if (map.from == map.to)
@ -1294,11 +1277,11 @@ static struct ip_conntrack_helper snmp_helper = {
.help = help,
.name = "snmp",
.tuple = { .src = { .u = { __constant_htons(SNMP_PORT) } },
.dst = { .protonum = IPPROTO_UDP },
.tuple = {.src = {.u = {.udp = {.port = __constant_htons(SNMP_PORT)}}},
.dst = {.protonum = IPPROTO_UDP},
},
.mask = { .src = { .u = { 0xFFFF } },
.dst = { .protonum = 0xFF },
.mask = {.src = {.u = {0xFFFF}},
.dst = {.protonum = 0xFF},
},
};
@ -1309,11 +1292,11 @@ static struct ip_conntrack_helper snmp_trap_helper = {
.help = help,
.name = "snmp_trap",
.tuple = { .src = { .u = { __constant_htons(SNMP_TRAP_PORT) } },
.dst = { .protonum = IPPROTO_UDP },
.tuple = {.src = {.u = {.udp = {.port = __constant_htons(SNMP_TRAP_PORT)}}},
.dst = {.protonum = IPPROTO_UDP},
},
.mask = { .src = { .u = { 0xFFFF } },
.dst = { .protonum = 0xFF },
.mask = {.src = {.u = {0xFFFF}},
.dst = {.protonum = 0xFF},
},
};