[NET]: Consolidate common code in net/core/filter.c

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 33 insertions, 57 deletions

diff --git a/net/core/filter.c b/net/core/filter.c
index e1267b465def..3923428a840f 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -36,7 +36,7 @@
 #include <linux/filter.h>
 
 /* No hurry in this branch */
-static u8 *load_pointer(struct sk_buff *skb, int k)
+static void *__load_pointer(struct sk_buff *skb, int k)
 {
         u8 *ptr = NULL;
 
@@ -50,6 +50,18 @@ static u8 *load_pointer(struct sk_buff *skb, int k)
         return NULL;
 }
 
+static inline void *load_pointer(struct sk_buff *skb, int k,
+                                 unsigned int size, void *buffer)
+{
+        if (k >= 0)
+                return skb_header_pointer(skb, k, size, buffer);
+        else {
+                if (k >= SKF_AD_OFF)
+                        return NULL;
+                return __load_pointer(skb, k);
+        }
+}
+
 /**
  *      sk_run_filter   -       run a filter on a socket
  *      @skb: buffer to run the filter on
@@ -64,15 +76,16 @@ static u8 *load_pointer(struct sk_buff *skb, int k)
  
 int sk_run_filter(struct sk_buff *skb, struct sock_filter *filter, int flen)
 {
-        unsigned char *data = skb->data;
         /* len is UNSIGNED. Byte wide insns relies only on implicit
            type casts to prevent reading arbitrary memory locations.
          */
         unsigned int len = skb->len-skb->data_len;
         struct sock_filter *fentry;     /* We walk down these */
+        void *ptr;
         u32 A = 0;                      /* Accumulator */
         u32 X = 0;                      /* Index Register */
         u32 mem[BPF_MEMWORDS];          /* Scratch Memory Store */
+        u32 tmp;
         int k;
         int pc;
 
@@ -168,67 +181,28 @@ int sk_run_filter(struct sk_buff *skb, struct sock_filter *filter, int flen)
                 case BPF_LD|BPF_W|BPF_ABS:
                         k = fentry->k;
  load_w:
-                        if (k < 0) {
-                                u8 *ptr;
-
-                                if (k >= SKF_AD_OFF)
-                                        break;
-                                ptr = load_pointer(skb, k);
-                                if (ptr) {
-                                        A = ntohl(*(u32*)ptr);
-                                        continue;
-                                }
-                        } else {
-                                u32 _tmp, *p;
-                                p = skb_header_pointer(skb, k, 4, &_tmp);
-                                if (p != NULL) {
-                                        A = ntohl(*p);
-                                        continue;
-                                }
+                        ptr = load_pointer(skb, k, 4, &tmp);
+                        if (ptr != NULL) {
+                                A = ntohl(*(u32 *)ptr);
+                                continue;
                         }
                         return 0;
                 case BPF_LD|BPF_H|BPF_ABS:
                         k = fentry->k;
  load_h:
-                        if (k < 0) {
-                                u8 *ptr;
-
-                                if (k >= SKF_AD_OFF)
-                                        break;
-                                ptr = load_pointer(skb, k);
-                                if (ptr) {
-                                        A = ntohs(*(u16*)ptr);
-                                        continue;
-                                }
-                        } else {
-                                u16 _tmp, *p;
-                                p = skb_header_pointer(skb, k, 2, &_tmp);
-                                if (p != NULL) {
-                                        A = ntohs(*p);
-                                        continue;
-                                }
+                        ptr = load_pointer(skb, k, 2, &tmp);
+                        if (ptr != NULL) {
+                                A = ntohs(*(u16 *)ptr);
+                                continue;
                         }
                         return 0;
                 case BPF_LD|BPF_B|BPF_ABS:
                         k = fentry->k;
 load_b:
-                        if (k < 0) {
-                                u8 *ptr;
-
-                                if (k >= SKF_AD_OFF)
-                                        break;
-                                ptr = load_pointer(skb, k);
-                                if (ptr) {
-                                        A = *ptr;
-                                        continue;
-                                }
-                        } else {
-                                u8 _tmp, *p;
-                                p = skb_header_pointer(skb, k, 1, &_tmp);
-                                if (p != NULL) {
-                                        A = *p;
-                                        continue;
-                                }
+                        ptr = load_pointer(skb, k, 1, &tmp);
+                        if (ptr != NULL) {
+                                A = *(u8 *)ptr;
+                                continue;
                         }
                         return 0;
                 case BPF_LD|BPF_W|BPF_LEN:
@@ -247,10 +221,12 @@ load_b:
                         k = X + fentry->k;
                         goto load_b;
                 case BPF_LDX|BPF_B|BPF_MSH:
-                        if (fentry->k >= len)
-                                return 0;
-                        X = (data[fentry->k] & 0xf) << 2;
-                        continue;
+                        ptr = load_pointer(skb, fentry->k, 1, &tmp);
+                        if (ptr != NULL) {
+                                X = (*(u8 *)ptr & 0xf) << 2;
+                                continue;
+                        }
+                        return 0;
                 case BPF_LD|BPF_IMM:
                         A = fentry->k;
                         continue;