esp: Introduce a helper to setup the trailer

We need to setup the trailer in two different cases,
so add a helper to avoid code duplication.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

2 files changed, 38 insertions, 50 deletions

diff --git a/net/ipv4/esp4.c b/net/ipv4/esp4.c
index 9e8d97133513..b1e24446e297 100644
--- a/net/ipv4/esp4.c
+++ b/net/ipv4/esp4.c
@@ -182,6 +182,22 @@ static void esp_output_done_esn(struct crypto_async_request *base, int err)
         esp_output_done(base, err);
 }
 
+static void esp_output_fill_trailer(u8 *tail, int tfclen, int plen, __u8 proto)
+{
+        /* Fill padding... */
+        if (tfclen) {
+                memset(tail, 0, tfclen);
+                tail += tfclen;
+        }
+        do {
+                int i;
+                for (i = 0; i < plen - 2; i++)
+                        tail[i] = i + 1;
+        } while (0);
+        tail[plen - 2] = plen - 2;
+        tail[plen - 1] = proto;
+}
+
 static int esp_output(struct xfrm_state *x, struct sk_buff *skb)
 {
         struct esp_output_extra *extra;
@@ -304,18 +320,7 @@ static int esp_output(struct xfrm_state *x, struct sk_buff *skb)
 
                         tail = vaddr + pfrag->offset;
 
-                        /* Fill padding... */
-                        if (tfclen) {
-                                memset(tail, 0, tfclen);
-                                tail += tfclen;
-                        }
-                        do {
-                                int i;
-                                for (i = 0; i < plen - 2; i++)
-                                        tail[i] = i + 1;
-                        } while (0);
-                        tail[plen - 2] = plen - 2;
-                        tail[plen - 1] = proto;
+                        esp_output_fill_trailer(tail, tfclen, plen, proto);
 
                         kunmap_atomic(vaddr);
 
@@ -395,20 +400,9 @@ cow:
         esph = ip_esp_hdr(skb);
 
 skip_cow:
-        /* Fill padding... */
-        if (tfclen) {
-                memset(tail, 0, tfclen);
-                tail += tfclen;
-        }
-        do {
-                int i;
-                for (i = 0; i < plen - 2; i++)
-                        tail[i] = i + 1;
-        } while (0);
-        tail[plen - 2] = plen - 2;
-        tail[plen - 1] = proto;
-        pskb_put(skb, trailer, clen - skb->len + alen);
+        esp_output_fill_trailer(tail, tfclen, plen, proto);
 
+        pskb_put(skb, trailer, clen - skb->len + alen);
         skb_push(skb, -skb_network_offset(skb));
         esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
         esph->spi = x->id.spi;
diff --git a/net/ipv6/esp6.c b/net/ipv6/esp6.c
index a428ac6b7c74..ff54faa75631 100644
--- a/net/ipv6/esp6.c
+++ b/net/ipv6/esp6.c
@@ -198,6 +198,22 @@ static void esp_output_done_esn(struct crypto_async_request *base, int err)
         esp_output_done(base, err);
 }
 
+static void esp_output_fill_trailer(u8 *tail, int tfclen, int plen, __u8 proto)
+{
+        /* Fill padding... */
+        if (tfclen) {
+                memset(tail, 0, tfclen);
+                tail += tfclen;
+        }
+        do {
+                int i;
+                for (i = 0; i < plen - 2; i++)
+                        tail[i] = i + 1;
+        } while (0);
+        tail[plen - 2] = plen - 2;
+        tail[plen - 1] = proto;
+}
+
 static int esp6_output(struct xfrm_state *x, struct sk_buff *skb)
 {
         int err;
@@ -284,18 +300,7 @@ static int esp6_output(struct xfrm_state *x, struct sk_buff *skb)
 
                         tail = vaddr + pfrag->offset;
 
-                        /* Fill padding... */
-                        if (tfclen) {
-                                memset(tail, 0, tfclen);
-                                tail += tfclen;
-                        }
-                        do {
-                                int i;
-                                for (i = 0; i < plen - 2; i++)
-                                        tail[i] = i + 1;
-                        } while (0);
-                        tail[plen - 2] = plen - 2;
-                        tail[plen - 1] = proto;
+                        esp_output_fill_trailer(tail, tfclen, plen, proto);
 
                         kunmap_atomic(vaddr);
 
@@ -375,20 +380,9 @@ cow:
         esph = ip_esp_hdr(skb);
 
 skip_cow:
-        /* Fill padding... */
-        if (tfclen) {
-                memset(tail, 0, tfclen);
-                tail += tfclen;
-        }
-        do {
-                int i;
-                for (i = 0; i < plen - 2; i++)
-                        tail[i] = i + 1;
-        } while (0);
-        tail[plen - 2] = plen - 2;
-        tail[plen - 1] = proto;
-        pskb_put(skb, trailer, clen - skb->len + alen);
+        esp_output_fill_trailer(tail, tfclen, plen, proto);
 
+        pskb_put(skb, trailer, clen - skb->len + alen);
         skb_push(skb, -skb_network_offset(skb));
 
         esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);