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Commit 5b14027b authored by Al Viro's avatar Al Viro Committed by David S. Miller
Browse files

[NETFILTER]: ip_nat_snmp_basic annotations. 



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

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 8e5200f5

net/ipv4/netfilter/ip_nat_snmp_basic.c

+34 −51
Original line number Diff line number Diff line
@@ -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;

	unsigned char s[4];



	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;

	}

	

	if (odd) new = nptr[0] * 256;

	else new = nptr[0];

	

	x += new & 0xFFFF;

	if (x & 0x10000) {

		x++;

		x &= 0xFFFF;

	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;

	}



	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)
@@ -1294,7 +1277,7 @@ static struct ip_conntrack_helper snmp_helper = { 
	.help = help,

	.name = "snmp",



	.tuple = { .src = { .u = { __constant_htons(SNMP_PORT) } },

	.tuple = {.src = {.u = {.udp = {.port = __constant_htons(SNMP_PORT)}}},

		  .dst = {.protonum = IPPROTO_UDP},

	},

	.mask = {.src = {.u = {0xFFFF}},
@@ -1309,7 +1292,7 @@ static struct ip_conntrack_helper snmp_trap_helper = { 
	.help = help,

	.name = "snmp_trap",



	.tuple = { .src = { .u = { __constant_htons(SNMP_TRAP_PORT) } },

	.tuple = {.src = {.u = {.udp = {.port = __constant_htons(SNMP_TRAP_PORT)}}},

		  .dst = {.protonum = IPPROTO_UDP},

	},

	.mask = {.src = {.u = {0xFFFF}},