| Message ID | e88d8905cf03bac8995be6d722f8b5abfc7afcc5.1464718103.git.marcelo.leitner@gmail.com |
|---|---|
| State | Changes Requested, archived |
| Delegated to: | David Miller |
| Headers | show |
On Tue, May 31, 2016 at 11:55 AM, Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> wrote: > skb_gso_network_seglen is not enough for checking fragment sizes if > skb is using GSO_BY_FRAGS as we have to check frag per frag. > > This patch introduces skb_gso_validate_mtu, based on the former, which > will wrap the use case inside it as all calls to skb_gso_network_seglen > were to validate if it fits on a given TMU, and improve the check. > > Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> > Tested-by: Xin Long <lucien.xin@gmail.com> > --- > include/linux/skbuff.h | 1 + > net/core/skbuff.c | 31 +++++++++++++++++++++++++++++++ > net/ipv4/ip_forward.c | 2 +- > net/ipv4/ip_output.c | 2 +- > net/ipv6/ip6_output.c | 2 +- > net/mpls/af_mpls.c | 2 +- > 6 files changed, 36 insertions(+), 4 deletions(-) > > diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h > index 1f713541cb2fc232cb0e8417232cb9942409c9fc..2109c2dc9767d454b2cd08696af039b6bcd1ace7 100644 > --- a/include/linux/skbuff.h > +++ b/include/linux/skbuff.h > @@ -2992,6 +2992,7 @@ void skb_split(struct sk_buff *skb, struct sk_buff *skb1, const u32 len); > int skb_shift(struct sk_buff *tgt, struct sk_buff *skb, int shiftlen); > void skb_scrub_packet(struct sk_buff *skb, bool xnet); > unsigned int skb_gso_transport_seglen(const struct sk_buff *skb); > +bool skb_gso_validate_mtu(const struct sk_buff *skb, unsigned int mtu); > struct sk_buff *skb_segment(struct sk_buff *skb, netdev_features_t features); > struct sk_buff *skb_vlan_untag(struct sk_buff *skb); > int skb_ensure_writable(struct sk_buff *skb, int write_len); > diff --git a/net/core/skbuff.c b/net/core/skbuff.c > index 97c32c75e704af1f31b064e8f1e0475ff1505d67..5ca562b56ec39d39e1225d96547e242732518ffe 100644 > --- a/net/core/skbuff.c > +++ b/net/core/skbuff.c > @@ -4392,6 +4392,37 @@ unsigned int skb_gso_transport_seglen(const struct sk_buff *skb) > } > EXPORT_SYMBOL_GPL(skb_gso_transport_seglen); > > +/** > + * skb_gso_validate_mtu - Return in case such skb fits a given MTU > + * > + * @skb: GSO skb > + * > + * skb_gso_validate_mtu validates if a given skb will fit a wanted MTU > + * once split. > + */ > +bool skb_gso_validate_mtu(const struct sk_buff *skb, unsigned int mtu) > +{ > + const struct skb_shared_info *shinfo = skb_shinfo(skb); > + const struct sk_buff *iter; > + unsigned int hlen; > + > + hlen = skb_gso_network_seglen(skb); > + > + if (shinfo->gso_size != GSO_BY_FRAGS) > + return hlen <= mtu; > + > + /* Undo this so we can re-use header sizes */ > + hlen -= GSO_BY_FRAGS; Isn't this just "hlen = 0"? If so you could probably just remove this line and the references to hlen below and instead just loop through verifying skb_headlen() instead of adding a value that should be 0. > + skb_walk_frags(skb, iter) { > + if (hlen + skb_headlen(iter) > mtu) > + return false; > + } > + > + return true; > +} > +EXPORT_SYMBOL_GPL(skb_gso_validate_mtu); > + > static struct sk_buff *skb_reorder_vlan_header(struct sk_buff *skb) > { > if (skb_cow(skb, skb_headroom(skb)) < 0) {
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 1f713541cb2fc232cb0e8417232cb9942409c9fc..2109c2dc9767d454b2cd08696af039b6bcd1ace7 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -2992,6 +2992,7 @@ void skb_split(struct sk_buff *skb, struct sk_buff *skb1, const u32 len); int skb_shift(struct sk_buff *tgt, struct sk_buff *skb, int shiftlen); void skb_scrub_packet(struct sk_buff *skb, bool xnet); unsigned int skb_gso_transport_seglen(const struct sk_buff *skb); +bool skb_gso_validate_mtu(const struct sk_buff *skb, unsigned int mtu); struct sk_buff *skb_segment(struct sk_buff *skb, netdev_features_t features); struct sk_buff *skb_vlan_untag(struct sk_buff *skb); int skb_ensure_writable(struct sk_buff *skb, int write_len); diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 97c32c75e704af1f31b064e8f1e0475ff1505d67..5ca562b56ec39d39e1225d96547e242732518ffe 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -4392,6 +4392,37 @@ unsigned int skb_gso_transport_seglen(const struct sk_buff *skb) } EXPORT_SYMBOL_GPL(skb_gso_transport_seglen); +/** + * skb_gso_validate_mtu - Return in case such skb fits a given MTU + * + * @skb: GSO skb + * + * skb_gso_validate_mtu validates if a given skb will fit a wanted MTU + * once split. + */ +bool skb_gso_validate_mtu(const struct sk_buff *skb, unsigned int mtu) +{ + const struct skb_shared_info *shinfo = skb_shinfo(skb); + const struct sk_buff *iter; + unsigned int hlen; + + hlen = skb_gso_network_seglen(skb); + + if (shinfo->gso_size != GSO_BY_FRAGS) + return hlen <= mtu; + + /* Undo this so we can re-use header sizes */ + hlen -= GSO_BY_FRAGS; + + skb_walk_frags(skb, iter) { + if (hlen + skb_headlen(iter) > mtu) + return false; + } + + return true; +} +EXPORT_SYMBOL_GPL(skb_gso_validate_mtu); + static struct sk_buff *skb_reorder_vlan_header(struct sk_buff *skb) { if (skb_cow(skb, skb_headroom(skb)) < 0) { diff --git a/net/ipv4/ip_forward.c b/net/ipv4/ip_forward.c index cbfb1808fcc490b94dc0bbdab6142acb8fa37815..9f0a7b96646f368021d9cd51bc3f728ba49eed0d 100644 --- a/net/ipv4/ip_forward.c +++ b/net/ipv4/ip_forward.c @@ -54,7 +54,7 @@ static bool ip_exceeds_mtu(const struct sk_buff *skb, unsigned int mtu) if (skb->ignore_df) return false; - if (skb_is_gso(skb) && skb_gso_network_seglen(skb) <= mtu) + if (skb_is_gso(skb) && skb_gso_validate_mtu(skb, mtu)) return false; return true; diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c index 124bf0a663283502deb03397343160d493a378b1..cbac493c913ac37b57a97314f9e7099b14b8246c 100644 --- a/net/ipv4/ip_output.c +++ b/net/ipv4/ip_output.c @@ -225,7 +225,7 @@ static int ip_finish_output_gso(struct net *net, struct sock *sk, /* common case: locally created skb or seglen is <= mtu */ if (((IPCB(skb)->flags & IPSKB_FORWARDED) == 0) || - skb_gso_network_seglen(skb) <= mtu) + skb_gso_validate_mtu(skb, mtu)) return ip_finish_output2(net, sk, skb); /* Slowpath - GSO segment length is exceeding the dst MTU. diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c index cbf127ae7c676650cc626cbf12cd61b6b570ea43..6b2f60a5c1de3063bb65c07b2b77c13f33890af8 100644 --- a/net/ipv6/ip6_output.c +++ b/net/ipv6/ip6_output.c @@ -368,7 +368,7 @@ static bool ip6_pkt_too_big(const struct sk_buff *skb, unsigned int mtu) if (skb->ignore_df) return false; - if (skb_is_gso(skb) && skb_gso_network_seglen(skb) <= mtu) + if (skb_is_gso(skb) && skb_gso_validate_mtu(skb, mtu)) return false; return true; diff --git a/net/mpls/af_mpls.c b/net/mpls/af_mpls.c index 0b80a7140cc494d8c39bd3efba2423272d1b8844..7a4aa3450dd71039e73516bd711ba7392493eb5e 100644 --- a/net/mpls/af_mpls.c +++ b/net/mpls/af_mpls.c @@ -91,7 +91,7 @@ bool mpls_pkt_too_big(const struct sk_buff *skb, unsigned int mtu) if (skb->len <= mtu) return false; - if (skb_is_gso(skb) && skb_gso_network_seglen(skb) <= mtu) + if (skb_is_gso(skb) && skb_gso_validate_mtu(skb, mtu)) return false; return true;