queue-4.4/net-create-skb_gso_validate_mac_len.patch

   1 From foo@baz Tue 04 Jun 2019 04:46:27 PM CEST
   2 From: Daniel Axtens <dja@axtens.net>
   3 Date: Wed, 31 Jan 2018 14:15:33 +1100
   4 Subject: net: create skb_gso_validate_mac_len()
   5
   6 From: Daniel Axtens <dja@axtens.net>
   7
   8 commit 2b16f048729bf35e6c28a40cbfad07239f9dcd90 upstream.
   9
  10 If you take a GSO skb, and split it into packets, will the MAC
  11 length (L2 + L3 + L4 headers + payload) of those packets be small
  12 enough to fit within a given length?
  13
  14 Move skb_gso_mac_seglen() to skbuff.h with other related functions
  15 like skb_gso_network_seglen() so we can use it, and then create
  16 skb_gso_validate_mac_len to do the full calculation.
  17
  18 Signed-off-by: Daniel Axtens <dja@axtens.net>
  19 Signed-off-by: David S. Miller <davem@davemloft.net>
  20 [bwh: Backported to 4.4: There is no GSO_BY_FRAGS case to handle, so
  21  skb_gso_validate_mac_len() becomes a trivial comparison. Put it inline in
  22  <linux/skbuff.h>.]
  23 Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
  24 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  25 ---
  26  include/linux/skbuff.h |   30 ++++++++++++++++++++++++++++++
  27  net/sched/sch_tbf.c    |   10 ----------
  28  2 files changed, 30 insertions(+), 10 deletions(-)
  29
  30 --- a/include/linux/skbuff.h
  31 +++ b/include/linux/skbuff.h
  32 @@ -3664,5 +3664,35 @@ static inline unsigned int skb_gso_netwo
  33         return hdr_len + skb_gso_transport_seglen(skb);
  34  }
  35
  36 +/**
  37 + * skb_gso_mac_seglen - Return length of individual segments of a gso packet
  38 + *
  39 + * @skb: GSO skb
  40 + *
  41 + * skb_gso_mac_seglen is used to determine the real size of the
  42 + * individual segments, including MAC/L2, Layer3 (IP, IPv6) and L4
  43 + * headers (TCP/UDP).
  44 + */
  45 +static inline unsigned int skb_gso_mac_seglen(const struct sk_buff *skb)
  46 +{
  47 +       unsigned int hdr_len = skb_transport_header(skb) - skb_mac_header(skb);
  48 +       return hdr_len + skb_gso_transport_seglen(skb);
  49 +}
  50 +
  51 +/**
  52 + * skb_gso_validate_mac_len - Will a split GSO skb fit in a given length?
  53 + *
  54 + * @skb: GSO skb
  55 + * @len: length to validate against
  56 + *
  57 + * skb_gso_validate_mac_len validates if a given skb will fit a wanted
  58 + * length once split, including L2, L3 and L4 headers and the payload.
  59 + */
  60 +static inline bool
  61 +skb_gso_validate_mac_len(const struct sk_buff *skb, unsigned int len)
  62 +{
  63 +       return skb_gso_mac_seglen(skb) <= len;
  64 +}
  65 +
  66  #endif /* __KERNEL__ */
  67  #endif /* _LINUX_SKBUFF_H */
  68 --- a/net/sched/sch_tbf.c
  69 +++ b/net/sched/sch_tbf.c
  70 @@ -142,16 +142,6 @@ static u64 psched_ns_t2l(const struct ps
  71         return len;
  72  }
  73
  74 -/*
  75 - * Return length of individual segments of a gso packet,
  76 - * including all headers (MAC, IP, TCP/UDP)
  77 - */
  78 -static unsigned int skb_gso_mac_seglen(const struct sk_buff *skb)
  79 -{
  80 -       unsigned int hdr_len = skb_transport_header(skb) - skb_mac_header(skb);
  81 -       return hdr_len + skb_gso_transport_seglen(skb);
  82 -}
  83 -
  84  /* GSO packet is too big, segment it so that tbf can transmit
  85   * each segment in time
  86   */