tree: https://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf-next.git
nft-bridge5
head: c8d511967c8897a2191b5e9c8695869d2af44bda
commit: 3553d2535f25f4593ef29d81e6d18a5ee16d1171 [5/8] net: ipv6: split large
skbuff into fragments infrastructure
reproduce:
# apt-get install sparse
git checkout 3553d2535f25f4593ef29d81e6d18a5ee16d1171
make ARCH=x86_64 allmodconfig
make C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__'
sparse warnings: (new ones prefixed by >>)
>> net/ipv6/ip6_output.c:755:16: sparse: Using plain integer as NULL pointer
net/ipv6/ip6_output.c:1379:24: sparse: expression using sizeof(void)
net/ipv6/ip6_output.c:1472:44: sparse: expression using sizeof(void)
net/ipv6/ip6_output.c:1611:32: sparse: expression using sizeof(void)
net/ipv6/ip6_output.c:1611:32: sparse: expression using sizeof(void)
vim +755 net/ipv6/ip6_output.c
682
683 struct sk_buff *ip6_frag_next(struct sk_buff *skb, struct
ip6_frag_state *state)
684 {
685 u8 *prevhdr = state->prevhdr, *fragnexthdr_offset;
686 struct sk_buff *frag;
687 struct frag_hdr *fh;
688 unsigned int len;
689
690 len = state->left;
691 /* IF: it doesn't fit, use 'mtu' - the data space left */
692 if (len > state->mtu)
693 len = state->mtu;
694 /* IF: we are not sending up to and including the packet end
695 then align the next start on an eight byte boundary */
696 if (len < state->left)
697 len &= ~7;
698
699 /* Allocate buffer */
700 frag = alloc_skb(len + state->hlen + sizeof(struct frag_hdr) +
701 state->hroom + state->troom, GFP_ATOMIC);
702 if (!frag)
703 return ERR_PTR(-ENOMEM);
704
705 /*
706 * Set up data on packet
707 */
708
709 ip6_copy_metadata(frag, skb);
710 skb_reserve(frag, state->hroom);
711 skb_put(frag, len + state->hlen + sizeof(struct frag_hdr));
712 skb_reset_network_header(frag);
713 fh = (struct frag_hdr *)(skb_network_header(frag) +
state->hlen);
714 frag->transport_header = (frag->network_header + state->hlen +
715 sizeof(struct frag_hdr));
716
717 /*
718 * Charge the memory for the fragment to any owner
719 * it might possess
720 */
721 if (skb->sk)
722 skb_set_owner_w(frag, skb->sk);
723
724 /*
725 * Copy the packet header into the new buffer.
726 */
727 skb_copy_from_linear_data(skb, skb_network_header(frag),
state->hlen);
728
729 fragnexthdr_offset = skb_network_header(frag);
730 fragnexthdr_offset += prevhdr - skb_network_header(skb);
731 *fragnexthdr_offset = NEXTHDR_FRAGMENT;
732
733 /*
734 * Build fragment header.
735 */
736 fh->nexthdr = state->nexthdr;
737 fh->reserved = 0;
738 fh->identification = state->frag_id;
739
740 /*
741 * Copy a block of the IP datagram.
742 */
743 BUG_ON(skb_copy_bits(skb, state->ptr,
skb_transport_header(frag),
744 len));
745 state->left -= len;
746
747 fh->frag_off = htons(state->offset);
748 if (state->left > 0)
749 fh->frag_off |= htons(IP6_MF);
750 ipv6_hdr(frag)->payload_len = htons(frag->len - sizeof(struct
ipv6hdr));
751
752 state->ptr += len;
753 state->offset += len;
754
> 755 return 0;
756 }
757 EXPORT_SYMBOL(ip6_frag_next);
758
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