net: core: don't account for udp header size when computing seglen
[firefly-linux-kernel-4.4.55.git] / net / core / skbuff.c
index 5976ef0846bdda08db6289bb91f05a63b85e6e3a..57e225c8914e2f64babae44ecb73628d5fedb4eb 100644 (file)
@@ -707,9 +707,6 @@ static void __copy_skb_header(struct sk_buff *new, const struct sk_buff *old)
        new->mark               = old->mark;
        new->skb_iif            = old->skb_iif;
        __nf_copy(new, old);
-#if IS_ENABLED(CONFIG_NETFILTER_XT_TARGET_TRACE)
-       new->nf_trace           = old->nf_trace;
-#endif
 #ifdef CONFIG_NET_SCHED
        new->tc_index           = old->tc_index;
 #ifdef CONFIG_NET_CLS_ACT
@@ -2130,25 +2127,31 @@ EXPORT_SYMBOL_GPL(skb_zerocopy_headlen);
  *
  *     The `hlen` as calculated by skb_zerocopy_headlen() specifies the
  *     headroom in the `to` buffer.
+ *
+ *     Return value:
+ *     0: everything is OK
+ *     -ENOMEM: couldn't orphan frags of @from due to lack of memory
+ *     -EFAULT: skb_copy_bits() found some problem with skb geometry
  */
-void
-skb_zerocopy(struct sk_buff *to, const struct sk_buff *from, int len, int hlen)
+int
+skb_zerocopy(struct sk_buff *to, struct sk_buff *from, int len, int hlen)
 {
        int i, j = 0;
        int plen = 0; /* length of skb->head fragment */
+       int ret;
        struct page *page;
        unsigned int offset;
 
        BUG_ON(!from->head_frag && !hlen);
 
        /* dont bother with small payloads */
-       if (len <= skb_tailroom(to)) {
-               skb_copy_bits(from, 0, skb_put(to, len), len);
-               return;
-       }
+       if (len <= skb_tailroom(to))
+               return skb_copy_bits(from, 0, skb_put(to, len), len);
 
        if (hlen) {
-               skb_copy_bits(from, 0, skb_put(to, hlen), hlen);
+               ret = skb_copy_bits(from, 0, skb_put(to, hlen), hlen);
+               if (unlikely(ret))
+                       return ret;
                len -= hlen;
        } else {
                plen = min_t(int, skb_headlen(from), len);
@@ -2166,6 +2169,11 @@ skb_zerocopy(struct sk_buff *to, const struct sk_buff *from, int len, int hlen)
        to->len += len + plen;
        to->data_len += len + plen;
 
+       if (unlikely(skb_orphan_frags(from, GFP_ATOMIC))) {
+               skb_tx_error(from);
+               return -ENOMEM;
+       }
+
        for (i = 0; i < skb_shinfo(from)->nr_frags; i++) {
                if (!len)
                        break;
@@ -2176,6 +2184,8 @@ skb_zerocopy(struct sk_buff *to, const struct sk_buff *from, int len, int hlen)
                j++;
        }
        skb_shinfo(to)->nr_frags = j;
+
+       return 0;
 }
 EXPORT_SYMBOL_GPL(skb_zerocopy);
 
@@ -2841,81 +2851,85 @@ EXPORT_SYMBOL_GPL(skb_pull_rcsum);
 
 /**
  *     skb_segment - Perform protocol segmentation on skb.
- *     @skb: buffer to segment
+ *     @head_skb: buffer to segment
  *     @features: features for the output path (see dev->features)
  *
  *     This function performs segmentation on the given skb.  It returns
  *     a pointer to the first in a list of new skbs for the segments.
  *     In case of error it returns ERR_PTR(err).
  */
-struct sk_buff *skb_segment(struct sk_buff *skb, netdev_features_t features)
+struct sk_buff *skb_segment(struct sk_buff *head_skb,
+                           netdev_features_t features)
 {
        struct sk_buff *segs = NULL;
        struct sk_buff *tail = NULL;
-       struct sk_buff *fskb = skb_shinfo(skb)->frag_list;
-       skb_frag_t *skb_frag = skb_shinfo(skb)->frags;
-       unsigned int mss = skb_shinfo(skb)->gso_size;
-       unsigned int doffset = skb->data - skb_mac_header(skb);
+       struct sk_buff *list_skb = skb_shinfo(head_skb)->frag_list;
+       skb_frag_t *frag = skb_shinfo(head_skb)->frags;
+       unsigned int mss = skb_shinfo(head_skb)->gso_size;
+       unsigned int doffset = head_skb->data - skb_mac_header(head_skb);
+       struct sk_buff *frag_skb = head_skb;
        unsigned int offset = doffset;
-       unsigned int tnl_hlen = skb_tnl_header_len(skb);
+       unsigned int tnl_hlen = skb_tnl_header_len(head_skb);
        unsigned int headroom;
        unsigned int len;
        __be16 proto;
        bool csum;
        int sg = !!(features & NETIF_F_SG);
-       int nfrags = skb_shinfo(skb)->nr_frags;
+       int nfrags = skb_shinfo(head_skb)->nr_frags;
        int err = -ENOMEM;
        int i = 0;
        int pos;
+       int dummy;
 
-       proto = skb_network_protocol(skb);
+       proto = skb_network_protocol(head_skb, &dummy);
        if (unlikely(!proto))
                return ERR_PTR(-EINVAL);
 
        csum = !!can_checksum_protocol(features, proto);
-       __skb_push(skb, doffset);
-       headroom = skb_headroom(skb);
-       pos = skb_headlen(skb);
+       __skb_push(head_skb, doffset);
+       headroom = skb_headroom(head_skb);
+       pos = skb_headlen(head_skb);
 
        do {
                struct sk_buff *nskb;
-               skb_frag_t *frag;
+               skb_frag_t *nskb_frag;
                int hsize;
                int size;
 
-               len = skb->len - offset;
+               len = head_skb->len - offset;
                if (len > mss)
                        len = mss;
 
-               hsize = skb_headlen(skb) - offset;
+               hsize = skb_headlen(head_skb) - offset;
                if (hsize < 0)
                        hsize = 0;
                if (hsize > len || !sg)
                        hsize = len;
 
-               if (!hsize && i >= nfrags && skb_headlen(fskb) &&
-                   (skb_headlen(fskb) == len || sg)) {
-                       BUG_ON(skb_headlen(fskb) > len);
+               if (!hsize && i >= nfrags && skb_headlen(list_skb) &&
+                   (skb_headlen(list_skb) == len || sg)) {
+                       BUG_ON(skb_headlen(list_skb) > len);
 
                        i = 0;
-                       nfrags = skb_shinfo(fskb)->nr_frags;
-                       skb_frag = skb_shinfo(fskb)->frags;
-                       pos += skb_headlen(fskb);
+                       nfrags = skb_shinfo(list_skb)->nr_frags;
+                       frag = skb_shinfo(list_skb)->frags;
+                       frag_skb = list_skb;
+                       pos += skb_headlen(list_skb);
 
                        while (pos < offset + len) {
                                BUG_ON(i >= nfrags);
 
-                               size = skb_frag_size(skb_frag);
+                               size = skb_frag_size(frag);
                                if (pos + size > offset + len)
                                        break;
 
                                i++;
                                pos += size;
-                               skb_frag++;
+                               frag++;
                        }
 
-                       nskb = skb_clone(fskb, GFP_ATOMIC);
-                       fskb = fskb->next;
+                       nskb = skb_clone(list_skb, GFP_ATOMIC);
+                       list_skb = list_skb->next;
 
                        if (unlikely(!nskb))
                                goto err;
@@ -2936,7 +2950,7 @@ struct sk_buff *skb_segment(struct sk_buff *skb, netdev_features_t features)
                        __skb_push(nskb, doffset);
                } else {
                        nskb = __alloc_skb(hsize + doffset + headroom,
-                                          GFP_ATOMIC, skb_alloc_rx_flag(skb),
+                                          GFP_ATOMIC, skb_alloc_rx_flag(head_skb),
                                           NUMA_NO_NODE);
 
                        if (unlikely(!nskb))
@@ -2952,12 +2966,12 @@ struct sk_buff *skb_segment(struct sk_buff *skb, netdev_features_t features)
                        segs = nskb;
                tail = nskb;
 
-               __copy_skb_header(nskb, skb);
-               nskb->mac_len = skb->mac_len;
+               __copy_skb_header(nskb, head_skb);
+               nskb->mac_len = head_skb->mac_len;
 
                skb_headers_offset_update(nskb, skb_headroom(nskb) - headroom);
 
-               skb_copy_from_linear_data_offset(skb, -tnl_hlen,
+               skb_copy_from_linear_data_offset(head_skb, -tnl_hlen,
                                                 nskb->data - tnl_hlen,
                                                 doffset + tnl_hlen);
 
@@ -2966,30 +2980,32 @@ struct sk_buff *skb_segment(struct sk_buff *skb, netdev_features_t features)
 
                if (!sg) {
                        nskb->ip_summed = CHECKSUM_NONE;
-                       nskb->csum = skb_copy_and_csum_bits(skb, offset,
+                       nskb->csum = skb_copy_and_csum_bits(head_skb, offset,
                                                            skb_put(nskb, len),
                                                            len, 0);
                        continue;
                }
 
-               frag = skb_shinfo(nskb)->frags;
+               nskb_frag = skb_shinfo(nskb)->frags;
 
-               skb_copy_from_linear_data_offset(skb, offset,
+               skb_copy_from_linear_data_offset(head_skb, offset,
                                                 skb_put(nskb, hsize), hsize);
 
-               skb_shinfo(nskb)->tx_flags = skb_shinfo(skb)->tx_flags & SKBTX_SHARED_FRAG;
+               skb_shinfo(nskb)->tx_flags = skb_shinfo(head_skb)->tx_flags &
+                       SKBTX_SHARED_FRAG;
 
                while (pos < offset + len) {
                        if (i >= nfrags) {
-                               BUG_ON(skb_headlen(fskb));
+                               BUG_ON(skb_headlen(list_skb));
 
                                i = 0;
-                               nfrags = skb_shinfo(fskb)->nr_frags;
-                               skb_frag = skb_shinfo(fskb)->frags;
+                               nfrags = skb_shinfo(list_skb)->nr_frags;
+                               frag = skb_shinfo(list_skb)->frags;
+                               frag_skb = list_skb;
 
                                BUG_ON(!nfrags);
 
-                               fskb = fskb->next;
+                               list_skb = list_skb->next;
                        }
 
                        if (unlikely(skb_shinfo(nskb)->nr_frags >=
@@ -3000,27 +3016,30 @@ struct sk_buff *skb_segment(struct sk_buff *skb, netdev_features_t features)
                                goto err;
                        }
 
-                       *frag = *skb_frag;
-                       __skb_frag_ref(frag);
-                       size = skb_frag_size(frag);
+                       if (unlikely(skb_orphan_frags(frag_skb, GFP_ATOMIC)))
+                               goto err;
+
+                       *nskb_frag = *frag;
+                       __skb_frag_ref(nskb_frag);
+                       size = skb_frag_size(nskb_frag);
 
                        if (pos < offset) {
-                               frag->page_offset += offset - pos;
-                               skb_frag_size_sub(frag, offset - pos);
+                               nskb_frag->page_offset += offset - pos;
+                               skb_frag_size_sub(nskb_frag, offset - pos);
                        }
 
                        skb_shinfo(nskb)->nr_frags++;
 
                        if (pos + size <= offset + len) {
                                i++;
-                               skb_frag++;
+                               frag++;
                                pos += size;
                        } else {
-                               skb_frag_size_sub(frag, pos + size - (offset + len));
+                               skb_frag_size_sub(nskb_frag, pos + size - (offset + len));
                                goto skip_fraglist;
                        }
 
-                       frag++;
+                       nskb_frag++;
                }
 
 skip_fraglist:
@@ -3034,7 +3053,7 @@ perform_csum_check:
                                                  nskb->len - doffset, 0);
                        nskb->ip_summed = CHECKSUM_NONE;
                }
-       } while ((offset += len) < skb->len);
+       } while ((offset += len) < head_skb->len);
 
        return segs;
 
@@ -3281,6 +3300,32 @@ __skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len)
        return elt;
 }
 
+/* As compared with skb_to_sgvec, skb_to_sgvec_nomark only map skb to given
+ * sglist without mark the sg which contain last skb data as the end.
+ * So the caller can mannipulate sg list as will when padding new data after
+ * the first call without calling sg_unmark_end to expend sg list.
+ *
+ * Scenario to use skb_to_sgvec_nomark:
+ * 1. sg_init_table
+ * 2. skb_to_sgvec_nomark(payload1)
+ * 3. skb_to_sgvec_nomark(payload2)
+ *
+ * This is equivalent to:
+ * 1. sg_init_table
+ * 2. skb_to_sgvec(payload1)
+ * 3. sg_unmark_end
+ * 4. skb_to_sgvec(payload2)
+ *
+ * When mapping mutilple payload conditionally, skb_to_sgvec_nomark
+ * is more preferable.
+ */
+int skb_to_sgvec_nomark(struct sk_buff *skb, struct scatterlist *sg,
+                       int offset, int len)
+{
+       return __skb_to_sgvec(skb, sg, offset, len);
+}
+EXPORT_SYMBOL_GPL(skb_to_sgvec_nomark);
+
 int skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len)
 {
        int nsg = __skb_to_sgvec(skb, sg, offset, len);
@@ -3543,15 +3588,47 @@ static int skb_maybe_pull_tail(struct sk_buff *skb, unsigned int len,
        return 0;
 }
 
+#define MAX_TCP_HDR_LEN (15 * 4)
+
+static __sum16 *skb_checksum_setup_ip(struct sk_buff *skb,
+                                     typeof(IPPROTO_IP) proto,
+                                     unsigned int off)
+{
+       switch (proto) {
+               int err;
+
+       case IPPROTO_TCP:
+               err = skb_maybe_pull_tail(skb, off + sizeof(struct tcphdr),
+                                         off + MAX_TCP_HDR_LEN);
+               if (!err && !skb_partial_csum_set(skb, off,
+                                                 offsetof(struct tcphdr,
+                                                          check)))
+                       err = -EPROTO;
+               return err ? ERR_PTR(err) : &tcp_hdr(skb)->check;
+
+       case IPPROTO_UDP:
+               err = skb_maybe_pull_tail(skb, off + sizeof(struct udphdr),
+                                         off + sizeof(struct udphdr));
+               if (!err && !skb_partial_csum_set(skb, off,
+                                                 offsetof(struct udphdr,
+                                                          check)))
+                       err = -EPROTO;
+               return err ? ERR_PTR(err) : &udp_hdr(skb)->check;
+       }
+
+       return ERR_PTR(-EPROTO);
+}
+
 /* This value should be large enough to cover a tagged ethernet header plus
  * maximally sized IP and TCP or UDP headers.
  */
 #define MAX_IP_HDR_LEN 128
 
-static int skb_checksum_setup_ip(struct sk_buff *skb, bool recalculate)
+static int skb_checksum_setup_ipv4(struct sk_buff *skb, bool recalculate)
 {
        unsigned int off;
        bool fragment;
+       __sum16 *csum;
        int err;
 
        fragment = false;
@@ -3572,51 +3649,15 @@ static int skb_checksum_setup_ip(struct sk_buff *skb, bool recalculate)
        if (fragment)
                goto out;
 
-       switch (ip_hdr(skb)->protocol) {
-       case IPPROTO_TCP:
-               err = skb_maybe_pull_tail(skb,
-                                         off + sizeof(struct tcphdr),
-                                         MAX_IP_HDR_LEN);
-               if (err < 0)
-                       goto out;
-
-               if (!skb_partial_csum_set(skb, off,
-                                         offsetof(struct tcphdr, check))) {
-                       err = -EPROTO;
-                       goto out;
-               }
-
-               if (recalculate)
-                       tcp_hdr(skb)->check =
-                               ~csum_tcpudp_magic(ip_hdr(skb)->saddr,
-                                                  ip_hdr(skb)->daddr,
-                                                  skb->len - off,
-                                                  IPPROTO_TCP, 0);
-               break;
-       case IPPROTO_UDP:
-               err = skb_maybe_pull_tail(skb,
-                                         off + sizeof(struct udphdr),
-                                         MAX_IP_HDR_LEN);
-               if (err < 0)
-                       goto out;
-
-               if (!skb_partial_csum_set(skb, off,
-                                         offsetof(struct udphdr, check))) {
-                       err = -EPROTO;
-                       goto out;
-               }
-
-               if (recalculate)
-                       udp_hdr(skb)->check =
-                               ~csum_tcpudp_magic(ip_hdr(skb)->saddr,
-                                                  ip_hdr(skb)->daddr,
-                                                  skb->len - off,
-                                                  IPPROTO_UDP, 0);
-               break;
-       default:
-               goto out;
-       }
+       csum = skb_checksum_setup_ip(skb, ip_hdr(skb)->protocol, off);
+       if (IS_ERR(csum))
+               return PTR_ERR(csum);
 
+       if (recalculate)
+               *csum = ~csum_tcpudp_magic(ip_hdr(skb)->saddr,
+                                          ip_hdr(skb)->daddr,
+                                          skb->len - off,
+                                          ip_hdr(skb)->protocol, 0);
        err = 0;
 
 out:
@@ -3639,6 +3680,7 @@ static int skb_checksum_setup_ipv6(struct sk_buff *skb, bool recalculate)
        unsigned int len;
        bool fragment;
        bool done;
+       __sum16 *csum;
 
        fragment = false;
        done = false;
@@ -3716,51 +3758,14 @@ static int skb_checksum_setup_ipv6(struct sk_buff *skb, bool recalculate)
        if (!done || fragment)
                goto out;
 
-       switch (nexthdr) {
-       case IPPROTO_TCP:
-               err = skb_maybe_pull_tail(skb,
-                                         off + sizeof(struct tcphdr),
-                                         MAX_IPV6_HDR_LEN);
-               if (err < 0)
-                       goto out;
-
-               if (!skb_partial_csum_set(skb, off,
-                                         offsetof(struct tcphdr, check))) {
-                       err = -EPROTO;
-                       goto out;
-               }
-
-               if (recalculate)
-                       tcp_hdr(skb)->check =
-                               ~csum_ipv6_magic(&ipv6_hdr(skb)->saddr,
-                                                &ipv6_hdr(skb)->daddr,
-                                                skb->len - off,
-                                                IPPROTO_TCP, 0);
-               break;
-       case IPPROTO_UDP:
-               err = skb_maybe_pull_tail(skb,
-                                         off + sizeof(struct udphdr),
-                                         MAX_IPV6_HDR_LEN);
-               if (err < 0)
-                       goto out;
-
-               if (!skb_partial_csum_set(skb, off,
-                                         offsetof(struct udphdr, check))) {
-                       err = -EPROTO;
-                       goto out;
-               }
-
-               if (recalculate)
-                       udp_hdr(skb)->check =
-                               ~csum_ipv6_magic(&ipv6_hdr(skb)->saddr,
-                                                &ipv6_hdr(skb)->daddr,
-                                                skb->len - off,
-                                                IPPROTO_UDP, 0);
-               break;
-       default:
-               goto out;
-       }
+       csum = skb_checksum_setup_ip(skb, nexthdr, off);
+       if (IS_ERR(csum))
+               return PTR_ERR(csum);
 
+       if (recalculate)
+               *csum = ~csum_ipv6_magic(&ipv6_hdr(skb)->saddr,
+                                        &ipv6_hdr(skb)->daddr,
+                                        skb->len - off, nexthdr, 0);
        err = 0;
 
 out:
@@ -3778,7 +3783,7 @@ int skb_checksum_setup(struct sk_buff *skb, bool recalculate)
 
        switch (skb->protocol) {
        case htons(ETH_P_IP):
-               err = skb_checksum_setup_ip(skb, recalculate);
+               err = skb_checksum_setup_ipv4(skb, recalculate);
                break;
 
        case htons(ETH_P_IPV6):
@@ -3932,12 +3937,14 @@ EXPORT_SYMBOL_GPL(skb_scrub_packet);
 unsigned int skb_gso_transport_seglen(const struct sk_buff *skb)
 {
        const struct skb_shared_info *shinfo = skb_shinfo(skb);
-       unsigned int hdr_len;
 
        if (likely(shinfo->gso_type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6)))
-               hdr_len = tcp_hdrlen(skb);
-       else
-               hdr_len = sizeof(struct udphdr);
-       return hdr_len + shinfo->gso_size;
+               return tcp_hdrlen(skb) + shinfo->gso_size;
+
+       /* UFO sets gso_size to the size of the fragmentation
+        * payload, i.e. the size of the L4 (UDP) header is already
+        * accounted for.
+        */
+       return shinfo->gso_size;
 }
 EXPORT_SYMBOL_GPL(skb_gso_transport_seglen);