[NETFILTER]: ip_nat_snmp_basic annotations.

... 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>

1 files changed, 34 insertions, 51 deletions

diff --git a/net/ipv4/netfilter/ip_nat_snmp_basic.c b/net/ipv4/netfilter/ip_nat_snmp_basic.c
index 168f45fa1898..c3d9f3b090c4 100644
--- a/net/ipv4/netfilter/ip_nat_snmp_basic.c
+++ b/net/ipv4/netfilter/ip_nat_snmp_basic.c
@@ -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;
-        }
-        
-        if (odd) new = nptr[0] * 256;
-        else new = nptr[0];
-        
-        x += new & 0xFFFF;
-        if (x & 0x10000) {
-                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;
         }
-        
-        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},
         },
 };