diff options
| author | Daniel Borkmann <daniel@iogearbox.net> | 2016-08-18 01:00:39 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2016-08-18 23:38:16 -0700 |
| commit | 5293efe62df81908f2e90c9820c7edcc8e61f5e9 (patch) | |
| tree | 6e3456c7bd339b1ebcfcebae0de6286635d44f33 /include/linux/skbuff.h | |
| parent | 45c7fffaf72e77baab9fd8ff1655540a1d5bac9f (diff) | |
| download | linux-5293efe62df81908f2e90c9820c7edcc8e61f5e9.tar.gz linux-5293efe62df81908f2e90c9820c7edcc8e61f5e9.tar.xz | |
bpf: add bpf_skb_change_tail helper
This work adds a bpf_skb_change_tail() helper for tc BPF programs. The
basic idea is to expand or shrink the skb in a controlled manner. The
eBPF program can then rewrite the rest via helpers like bpf_skb_store_bytes(),
bpf_lX_csum_replace() and others rather than passing a raw buffer for
writing here.
bpf_skb_change_tail() is really a slow path helper and intended for
replies with f.e. ICMP control messages. Concept is similar to other
helpers like bpf_skb_change_proto() helper to keep the helper without
protocol specifics and let the BPF program mangle the remaining parts.
A flags field has been added and is reserved for now should we extend
the helper in future.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/linux/skbuff.h')
| -rw-r--r-- | include/linux/skbuff.h | 43 |
1 files changed, 42 insertions, 1 deletions
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 0f665cb26b50..7047448e8129 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -2295,7 +2295,7 @@ static inline int pskb_network_may_pull(struct sk_buff *skb, unsigned int len) int ___pskb_trim(struct sk_buff *skb, unsigned int len); -static inline void __skb_trim(struct sk_buff *skb, unsigned int len) +static inline void __skb_set_length(struct sk_buff *skb, unsigned int len) { if (unlikely(skb_is_nonlinear(skb))) { WARN_ON(1); @@ -2305,6 +2305,11 @@ static inline void __skb_trim(struct sk_buff *skb, unsigned int len) skb_set_tail_pointer(skb, len); } +static inline void __skb_trim(struct sk_buff *skb, unsigned int len) +{ + __skb_set_length(skb, len); +} + void skb_trim(struct sk_buff *skb, unsigned int len); static inline int __pskb_trim(struct sk_buff *skb, unsigned int len) @@ -2335,6 +2340,20 @@ static inline void pskb_trim_unique(struct sk_buff *skb, unsigned int len) BUG_ON(err); } +static inline int __skb_grow(struct sk_buff *skb, unsigned int len) +{ + unsigned int diff = len - skb->len; + + if (skb_tailroom(skb) < diff) { + int ret = pskb_expand_head(skb, 0, diff - skb_tailroom(skb), + GFP_ATOMIC); + if (ret) + return ret; + } + __skb_set_length(skb, len); + return 0; +} + /** * skb_orphan - orphan a buffer * @skb: buffer to orphan @@ -2938,6 +2957,21 @@ static inline int pskb_trim_rcsum(struct sk_buff *skb, unsigned int len) return __pskb_trim(skb, len); } +static inline int __skb_trim_rcsum(struct sk_buff *skb, unsigned int len) +{ + if (skb->ip_summed == CHECKSUM_COMPLETE) + skb->ip_summed = CHECKSUM_NONE; + __skb_trim(skb, len); + return 0; +} + +static inline int __skb_grow_rcsum(struct sk_buff *skb, unsigned int len) +{ + if (skb->ip_summed == CHECKSUM_COMPLETE) + skb->ip_summed = CHECKSUM_NONE; + return __skb_grow(skb, len); +} + #define skb_queue_walk(queue, skb) \ for (skb = (queue)->next; \ skb != (struct sk_buff *)(queue); \ @@ -3726,6 +3760,13 @@ static inline bool skb_is_gso_v6(const struct sk_buff *skb) return skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6; } +static inline void skb_gso_reset(struct sk_buff *skb) +{ + skb_shinfo(skb)->gso_size = 0; + skb_shinfo(skb)->gso_segs = 0; + skb_shinfo(skb)->gso_type = 0; +} + void __skb_warn_lro_forwarding(const struct sk_buff *skb); static inline bool skb_warn_if_lro(const struct sk_buff *skb) |