From: Daniel Axtens dja@axtens.net
commit 2b16f048729bf35e6c28a40cbfad07239f9dcd90 upstream.
If you take a GSO skb, and split it into packets, will the MAC length (L2 + L3 + L4 headers + payload) of those packets be small enough to fit within a given length?
Move skb_gso_mac_seglen() to skbuff.h with other related functions like skb_gso_network_seglen() so we can use it, and then create skb_gso_validate_mac_len to do the full calculation.
Signed-off-by: Daniel Axtens dja@axtens.net Signed-off-by: David S. Miller davem@davemloft.net [bwh: Backported to 4.4: There is no GSO_BY_FRAGS case to handle, so skb_gso_validate_mac_len() becomes a trivial comparison. Put it inline in <linux/skbuff.h>.] Signed-off-by: Ben Hutchings ben.hutchings@codethink.co.uk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- include/linux/skbuff.h | 30 ++++++++++++++++++++++++++++++ net/sched/sch_tbf.c | 10 ---------- 2 files changed, 30 insertions(+), 10 deletions(-)
--- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -3664,5 +3664,35 @@ static inline unsigned int skb_gso_netwo return hdr_len + skb_gso_transport_seglen(skb); }
+/** + * skb_gso_mac_seglen - Return length of individual segments of a gso packet + * + * @skb: GSO skb + * + * skb_gso_mac_seglen is used to determine the real size of the + * individual segments, including MAC/L2, Layer3 (IP, IPv6) and L4 + * headers (TCP/UDP). + */ +static inline unsigned int skb_gso_mac_seglen(const struct sk_buff *skb) +{ + unsigned int hdr_len = skb_transport_header(skb) - skb_mac_header(skb); + return hdr_len + skb_gso_transport_seglen(skb); +} + +/** + * skb_gso_validate_mac_len - Will a split GSO skb fit in a given length? + * + * @skb: GSO skb + * @len: length to validate against + * + * skb_gso_validate_mac_len validates if a given skb will fit a wanted + * length once split, including L2, L3 and L4 headers and the payload. + */ +static inline bool +skb_gso_validate_mac_len(const struct sk_buff *skb, unsigned int len) +{ + return skb_gso_mac_seglen(skb) <= len; +} + #endif /* __KERNEL__ */ #endif /* _LINUX_SKBUFF_H */ --- a/net/sched/sch_tbf.c +++ b/net/sched/sch_tbf.c @@ -142,16 +142,6 @@ static u64 psched_ns_t2l(const struct ps return len; }
-/* - * Return length of individual segments of a gso packet, - * including all headers (MAC, IP, TCP/UDP) - */ -static unsigned int skb_gso_mac_seglen(const struct sk_buff *skb) -{ - unsigned int hdr_len = skb_transport_header(skb) - skb_mac_header(skb); - return hdr_len + skb_gso_transport_seglen(skb); -} - /* GSO packet is too big, segment it so that tbf can transmit * each segment in time */