From d27cf5c59a12f66425df29cd81f61aa73ef14ac1 Mon Sep 17 00:00:00 2001 From: John Hurley Date: Sun, 7 Jul 2019 15:01:56 +0100 Subject: [PATCH] net: core: add MPLS update core helper and use in OvS Open vSwitch allows the updating of an existing MPLS header on a packet. In preparation for supporting similar functionality in TC, move this to a common skb helper function. Signed-off-by: John Hurley Reviewed-by: Jakub Kicinski Reviewed-by: Simon Horman Reviewed-by: Willem de Bruijn Acked-by: Cong Wang Signed-off-by: David S. Miller --- include/linux/skbuff.h | 1 + net/core/skbuff.c | 33 +++++++++++++++++++++++++++++++++ net/openvswitch/actions.c | 13 +++---------- 3 files changed, 37 insertions(+), 10 deletions(-) diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 08d1c8e70540..9f7e01f2be83 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -3449,6 +3449,7 @@ int skb_vlan_pop(struct sk_buff *skb); int skb_vlan_push(struct sk_buff *skb, __be16 vlan_proto, u16 vlan_tci); int skb_mpls_push(struct sk_buff *skb, __be32 mpls_lse, __be16 mpls_proto); int skb_mpls_pop(struct sk_buff *skb, __be16 next_proto); +int skb_mpls_update_lse(struct sk_buff *skb, __be32 mpls_lse); struct sk_buff *pskb_extract(struct sk_buff *skb, int off, int to_copy, gfp_t gfp); diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 8c00be4d8919..93443a01ab39 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -5531,6 +5531,39 @@ int skb_mpls_pop(struct sk_buff *skb, __be16 next_proto) } EXPORT_SYMBOL_GPL(skb_mpls_pop); +/** + * skb_mpls_update_lse() - modify outermost MPLS header and update csum + * + * @skb: buffer + * @mpls_lse: new MPLS label stack entry to update to + * + * Expects skb->data at mac header. + * + * Returns 0 on success, -errno otherwise. + */ +int skb_mpls_update_lse(struct sk_buff *skb, __be32 mpls_lse) +{ + int err; + + if (unlikely(!eth_p_mpls(skb->protocol))) + return -EINVAL; + + err = skb_ensure_writable(skb, skb->mac_len + MPLS_HLEN); + if (unlikely(err)) + return err; + + if (skb->ip_summed == CHECKSUM_COMPLETE) { + __be32 diff[] = { ~mpls_hdr(skb)->label_stack_entry, mpls_lse }; + + skb->csum = csum_partial((char *)diff, sizeof(diff), skb->csum); + } + + mpls_hdr(skb)->label_stack_entry = mpls_lse; + + return 0; +} +EXPORT_SYMBOL_GPL(skb_mpls_update_lse); + /** * alloc_skb_with_frags - allocate skb with page frags * diff --git a/net/openvswitch/actions.c b/net/openvswitch/actions.c index 62715bb8d611..3572e11b6f21 100644 --- a/net/openvswitch/actions.c +++ b/net/openvswitch/actions.c @@ -193,19 +193,12 @@ static int set_mpls(struct sk_buff *skb, struct sw_flow_key *flow_key, __be32 lse; int err; - err = skb_ensure_writable(skb, skb->mac_len + MPLS_HLEN); - if (unlikely(err)) - return err; - stack = mpls_hdr(skb); lse = OVS_MASKED(stack->label_stack_entry, *mpls_lse, *mask); - if (skb->ip_summed == CHECKSUM_COMPLETE) { - __be32 diff[] = { ~(stack->label_stack_entry), lse }; + err = skb_mpls_update_lse(skb, lse); + if (err) + return err; - skb->csum = csum_partial((char *)diff, sizeof(diff), skb->csum); - } - - stack->label_stack_entry = lse; flow_key->mpls.top_lse = lse; return 0; }