From 8822e270d697010e6a4fd42a319dbefc33db91e1 Mon Sep 17 00:00:00 2001 From: John Hurley Date: Sun, 7 Jul 2019 15:01:54 +0100 Subject: [PATCH] net: core: move push MPLS functionality from OvS to core helper Open vSwitch provides code to push an MPLS header to a packet. In preparation for supporting this in TC, move the push code to an skb helper that can be reused. 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 | 64 +++++++++++++++++++++++++++++++++++++++ net/openvswitch/actions.c | 31 +++---------------- 3 files changed, 69 insertions(+), 27 deletions(-) diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 1fdfdbb34e8e..1dc55000710c 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -3447,6 +3447,7 @@ int skb_ensure_writable(struct sk_buff *skb, int write_len); int __skb_vlan_pop(struct sk_buff *skb, u16 *vlan_tci); 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); 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 cdb0ccdaac0b..495fd743a935 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -66,6 +66,7 @@ #include #include #include +#include #include #include @@ -5425,6 +5426,69 @@ int skb_vlan_push(struct sk_buff *skb, __be16 vlan_proto, u16 vlan_tci) } EXPORT_SYMBOL(skb_vlan_push); +/* Update the ethertype of hdr and the skb csum value if required. */ +static void skb_mod_eth_type(struct sk_buff *skb, struct ethhdr *hdr, + __be16 ethertype) +{ + if (skb->ip_summed == CHECKSUM_COMPLETE) { + __be16 diff[] = { ~hdr->h_proto, ethertype }; + + skb->csum = csum_partial((char *)diff, sizeof(diff), skb->csum); + } + + hdr->h_proto = ethertype; +} + +/** + * skb_mpls_push() - push a new MPLS header after the mac header + * + * @skb: buffer + * @mpls_lse: MPLS label stack entry to push + * @mpls_proto: ethertype of the new MPLS header (expects 0x8847 or 0x8848) + * + * Expects skb->data at mac header. + * + * Returns 0 on success, -errno otherwise. + */ +int skb_mpls_push(struct sk_buff *skb, __be32 mpls_lse, __be16 mpls_proto) +{ + struct mpls_shim_hdr *lse; + int err; + + if (unlikely(!eth_p_mpls(mpls_proto))) + return -EINVAL; + + /* Networking stack does not allow simultaneous Tunnel and MPLS GSO. */ + if (skb->encapsulation) + return -EINVAL; + + err = skb_cow_head(skb, MPLS_HLEN); + if (unlikely(err)) + return err; + + if (!skb->inner_protocol) { + skb_set_inner_network_header(skb, skb->mac_len); + skb_set_inner_protocol(skb, skb->protocol); + } + + skb_push(skb, MPLS_HLEN); + memmove(skb_mac_header(skb) - MPLS_HLEN, skb_mac_header(skb), + skb->mac_len); + skb_reset_mac_header(skb); + skb_set_network_header(skb, skb->mac_len); + + lse = mpls_hdr(skb); + lse->label_stack_entry = mpls_lse; + skb_postpush_rcsum(skb, lse, MPLS_HLEN); + + if (skb->dev && skb->dev->type == ARPHRD_ETHER) + skb_mod_eth_type(skb, eth_hdr(skb), mpls_proto); + skb->protocol = mpls_proto; + + return 0; +} +EXPORT_SYMBOL_GPL(skb_mpls_push); + /** * alloc_skb_with_frags - allocate skb with page frags * diff --git a/net/openvswitch/actions.c b/net/openvswitch/actions.c index bd131469e4ca..a9a6c9cbf946 100644 --- a/net/openvswitch/actions.c +++ b/net/openvswitch/actions.c @@ -175,34 +175,11 @@ static void update_ethertype(struct sk_buff *skb, struct ethhdr *hdr, static int push_mpls(struct sk_buff *skb, struct sw_flow_key *key, const struct ovs_action_push_mpls *mpls) { - struct mpls_shim_hdr *new_mpls_lse; + int err; - /* Networking stack do not allow simultaneous Tunnel and MPLS GSO. */ - if (skb->encapsulation) - return -ENOTSUPP; - - if (skb_cow_head(skb, MPLS_HLEN) < 0) - return -ENOMEM; - - if (!skb->inner_protocol) { - skb_set_inner_network_header(skb, skb->mac_len); - skb_set_inner_protocol(skb, skb->protocol); - } - - skb_push(skb, MPLS_HLEN); - memmove(skb_mac_header(skb) - MPLS_HLEN, skb_mac_header(skb), - skb->mac_len); - skb_reset_mac_header(skb); - skb_set_network_header(skb, skb->mac_len); - - new_mpls_lse = mpls_hdr(skb); - new_mpls_lse->label_stack_entry = mpls->mpls_lse; - - skb_postpush_rcsum(skb, new_mpls_lse, MPLS_HLEN); - - if (ovs_key_mac_proto(key) == MAC_PROTO_ETHERNET) - update_ethertype(skb, eth_hdr(skb), mpls->mpls_ethertype); - skb->protocol = mpls->mpls_ethertype; + err = skb_mpls_push(skb, mpls->mpls_lse, mpls->mpls_ethertype); + if (err) + return err; invalidate_flow_key(key); return 0;