From 1a37e412a0225fcba5587f24c0dfc7636efc8b69 Mon Sep 17 00:00:00 2001 From: Simon Horman Date: Thu, 23 May 2013 21:02:51 +0000 Subject: [PATCH 1/2] net: Use 16bits for *_headers fields of struct skbuff In order to mitigate ongoing incresase in the size of struct skbuff use 16 bit integer offsets rather than pointers for inner_*_headers. This appears to reduce the size of struct skbuff from 0xd0 to 0xc0 bytes on x86_64 with the following all unset. CONFIG_XFRM CONFIG_NF_CONNTRACK CONFIG_NF_CONNTRACK_MODULE NET_SKBUFF_NF_DEFRAG_NEEDED CONFIG_BRIDGE_NETFILTER CONFIG_NET_SCHED CONFIG_IPV6_NDISC_NODETYPE CONFIG_NET_DMA CONFIG_NETWORK_SECMARK Signed-off-by: Simon Horman Signed-off-by: David S. Miller --- include/linux/skbuff.h | 119 +++-------------------------------------- 1 file changed, 6 insertions(+), 113 deletions(-) diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 2e0ced1af3b10..5663e35927848 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -509,12 +509,12 @@ struct sk_buff { __u32 reserved_tailroom; }; - sk_buff_data_t inner_transport_header; - sk_buff_data_t inner_network_header; - sk_buff_data_t inner_mac_header; - sk_buff_data_t transport_header; - sk_buff_data_t network_header; - sk_buff_data_t mac_header; + __u16 inner_transport_header; + __u16 inner_network_header; + __u16 inner_mac_header; + __u16 transport_header; + __u16 network_header; + __u16 mac_header; /* These elements must be at the end, see alloc_skb() for details. */ sk_buff_data_t tail; sk_buff_data_t end; @@ -1527,7 +1527,6 @@ static inline void skb_reset_mac_len(struct sk_buff *skb) skb->mac_len = skb->network_header - skb->mac_header; } -#ifdef NET_SKBUFF_DATA_USES_OFFSET static inline unsigned char *skb_inner_transport_header(const struct sk_buff *skb) { @@ -1638,112 +1637,6 @@ static inline void skb_set_mac_header(struct sk_buff *skb, const int offset) skb->mac_header += offset; } -#else /* NET_SKBUFF_DATA_USES_OFFSET */ -static inline unsigned char *skb_inner_transport_header(const struct sk_buff - *skb) -{ - return skb->inner_transport_header; -} - -static inline void skb_reset_inner_transport_header(struct sk_buff *skb) -{ - skb->inner_transport_header = skb->data; -} - -static inline void skb_set_inner_transport_header(struct sk_buff *skb, - const int offset) -{ - skb->inner_transport_header = skb->data + offset; -} - -static inline unsigned char *skb_inner_network_header(const struct sk_buff *skb) -{ - return skb->inner_network_header; -} - -static inline void skb_reset_inner_network_header(struct sk_buff *skb) -{ - skb->inner_network_header = skb->data; -} - -static inline void skb_set_inner_network_header(struct sk_buff *skb, - const int offset) -{ - skb->inner_network_header = skb->data + offset; -} - -static inline unsigned char *skb_inner_mac_header(const struct sk_buff *skb) -{ - return skb->inner_mac_header; -} - -static inline void skb_reset_inner_mac_header(struct sk_buff *skb) -{ - skb->inner_mac_header = skb->data; -} - -static inline void skb_set_inner_mac_header(struct sk_buff *skb, - const int offset) -{ - skb->inner_mac_header = skb->data + offset; -} -static inline bool skb_transport_header_was_set(const struct sk_buff *skb) -{ - return skb->transport_header != NULL; -} - -static inline unsigned char *skb_transport_header(const struct sk_buff *skb) -{ - return skb->transport_header; -} - -static inline void skb_reset_transport_header(struct sk_buff *skb) -{ - skb->transport_header = skb->data; -} - -static inline void skb_set_transport_header(struct sk_buff *skb, - const int offset) -{ - skb->transport_header = skb->data + offset; -} - -static inline unsigned char *skb_network_header(const struct sk_buff *skb) -{ - return skb->network_header; -} - -static inline void skb_reset_network_header(struct sk_buff *skb) -{ - skb->network_header = skb->data; -} - -static inline void skb_set_network_header(struct sk_buff *skb, const int offset) -{ - skb->network_header = skb->data + offset; -} - -static inline unsigned char *skb_mac_header(const struct sk_buff *skb) -{ - return skb->mac_header; -} - -static inline int skb_mac_header_was_set(const struct sk_buff *skb) -{ - return skb->mac_header != NULL; -} - -static inline void skb_reset_mac_header(struct sk_buff *skb) -{ - skb->mac_header = skb->data; -} - -static inline void skb_set_mac_header(struct sk_buff *skb, const int offset) -{ - skb->mac_header = skb->data + offset; -} -#endif /* NET_SKBUFF_DATA_USES_OFFSET */ - static inline void skb_probe_transport_header(struct sk_buff *skb, const int offset_hint) { From 0d89d2035fe063461a5ddb609b2c12e7fb006e44 Mon Sep 17 00:00:00 2001 From: Simon Horman Date: Thu, 23 May 2013 21:02:52 +0000 Subject: [PATCH 2/2] MPLS: Add limited GSO support In the case where a non-MPLS packet is received and an MPLS stack is added it may well be the case that the original skb is GSO but the NIC used for transmit does not support GSO of MPLS packets. The aim of this code is to provide GSO in software for MPLS packets whose skbs are GSO. SKB Usage: When an implementation adds an MPLS stack to a non-MPLS packet it should do the following to skb metadata: * Set skb->inner_protocol to the old non-MPLS ethertype of the packet. skb->inner_protocol is added by this patch. * Set skb->protocol to the new MPLS ethertype of the packet. * Set skb->network_header to correspond to the end of the L3 header, including the MPLS label stack. I have posted a patch, "[PATCH v3.29] datapath: Add basic MPLS support to kernel" which adds MPLS support to the kernel datapath of Open vSwtich. That patch sets the above requirements in datapath/actions.c:push_mpls() and was used to exercise this code. The datapath patch is against the Open vSwtich tree but it is intended that it be added to the Open vSwtich code present in the mainline Linux kernel at some point. Features: I believe that the approach that I have taken is at least partially consistent with the handling of other protocols. Jesse, I understand that you have some ideas here. I am more than happy to change my implementation. This patch adds dev->mpls_features which may be used by devices to advertise features supported for MPLS packets. A new NETIF_F_MPLS_GSO feature is added for devices which support hardware MPLS GSO offload. Currently no devices support this and MPLS GSO always falls back to software. Alternate Implementation: One possible alternate implementation is to teach netif_skb_features() and skb_network_protocol() about MPLS, in a similar way to their understanding of VLANs. I believe this would avoid the need for net/mpls/mpls_gso.c and in particular the calls to __skb_push() and __skb_push() in mpls_gso_segment(). I have decided on the implementation in this patch as it should not introduce any overhead in the case where mpls_gso is not compiled into the kernel or inserted as a module. MPLS GSO suggested by Jesse Gross. Based in part on "v4 GRE: Add TCP segmentation offload for GRE" by Pravin B Shelar. Cc: Jesse Gross Cc: Pravin B Shelar Signed-off-by: Simon Horman Signed-off-by: David S. Miller --- include/linux/netdev_features.h | 4 +- include/linux/netdevice.h | 2 + include/linux/skbuff.h | 4 ++ net/Kconfig | 1 + net/Makefile | 1 + net/core/dev.c | 4 ++ net/core/ethtool.c | 1 + net/ipv4/af_inet.c | 1 + net/ipv4/tcp.c | 1 + net/ipv4/udp.c | 2 +- net/ipv6/ip6_offload.c | 1 + net/ipv6/udp_offload.c | 3 +- net/mpls/Kconfig | 9 +++ net/mpls/Makefile | 4 ++ net/mpls/mpls_gso.c | 108 ++++++++++++++++++++++++++++++++ 15 files changed, 143 insertions(+), 3 deletions(-) create mode 100644 net/mpls/Kconfig create mode 100644 net/mpls/Makefile create mode 100644 net/mpls/mpls_gso.c diff --git a/include/linux/netdev_features.h b/include/linux/netdev_features.h index 09906b7ca47d6..a2a89a5c7be55 100644 --- a/include/linux/netdev_features.h +++ b/include/linux/netdev_features.h @@ -43,8 +43,9 @@ enum { NETIF_F_FSO_BIT, /* ... FCoE segmentation */ NETIF_F_GSO_GRE_BIT, /* ... GRE with TSO */ NETIF_F_GSO_UDP_TUNNEL_BIT, /* ... UDP TUNNEL with TSO */ + NETIF_F_GSO_MPLS_BIT, /* ... MPLS segmentation */ /**/NETIF_F_GSO_LAST = /* last bit, see GSO_MASK */ - NETIF_F_GSO_UDP_TUNNEL_BIT, + NETIF_F_GSO_MPLS_BIT, NETIF_F_FCOE_CRC_BIT, /* FCoE CRC32 */ NETIF_F_SCTP_CSUM_BIT, /* SCTP checksum offload */ @@ -107,6 +108,7 @@ enum { #define NETIF_F_RXALL __NETIF_F(RXALL) #define NETIF_F_GSO_GRE __NETIF_F(GSO_GRE) #define NETIF_F_GSO_UDP_TUNNEL __NETIF_F(GSO_UDP_TUNNEL) +#define NETIF_F_GSO_MPLS __NETIF_F(GSO_MPLS) #define NETIF_F_HW_VLAN_STAG_FILTER __NETIF_F(HW_VLAN_STAG_FILTER) #define NETIF_F_HW_VLAN_STAG_RX __NETIF_F(HW_VLAN_STAG_RX) #define NETIF_F_HW_VLAN_STAG_TX __NETIF_F(HW_VLAN_STAG_TX) diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index ea7b6bce9ea07..6b2bb460d1d75 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -1088,6 +1088,8 @@ struct net_device { * need to set them appropriately. */ netdev_features_t hw_enc_features; + /* mask of fetures inheritable by MPLS */ + netdev_features_t mpls_features; /* Interface index. Unique device identifier */ int ifindex; diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 5663e35927848..8f2b830772a87 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -319,6 +319,8 @@ enum { SKB_GSO_GRE = 1 << 6, SKB_GSO_UDP_TUNNEL = 1 << 7, + + SKB_GSO_MPLS = 1 << 8, }; #if BITS_PER_LONG > 32 @@ -389,6 +391,7 @@ typedef unsigned char *sk_buff_data_t; * @dropcount: total number of sk_receive_queue overflows * @vlan_proto: vlan encapsulation protocol * @vlan_tci: vlan tag control information + * @inner_protocol: Protocol (encapsulation) * @inner_transport_header: Inner transport layer header (encapsulation) * @inner_network_header: Network layer header (encapsulation) * @inner_mac_header: Link layer header (encapsulation) @@ -509,6 +512,7 @@ struct sk_buff { __u32 reserved_tailroom; }; + __be16 inner_protocol; __u16 inner_transport_header; __u16 inner_network_header; __u16 inner_mac_header; diff --git a/net/Kconfig b/net/Kconfig index 08de901415ee6..523e43e6da1b9 100644 --- a/net/Kconfig +++ b/net/Kconfig @@ -218,6 +218,7 @@ source "net/batman-adv/Kconfig" source "net/openvswitch/Kconfig" source "net/vmw_vsock/Kconfig" source "net/netlink/Kconfig" +source "net/mpls/Kconfig" config RPS boolean diff --git a/net/Makefile b/net/Makefile index 091e7b04f3015..9492e8cb64e9e 100644 --- a/net/Makefile +++ b/net/Makefile @@ -70,3 +70,4 @@ obj-$(CONFIG_BATMAN_ADV) += batman-adv/ obj-$(CONFIG_NFC) += nfc/ obj-$(CONFIG_OPENVSWITCH) += openvswitch/ obj-$(CONFIG_VSOCKETS) += vmw_vsock/ +obj-$(CONFIG_NET_MPLS_GSO) += mpls/ diff --git a/net/core/dev.c b/net/core/dev.c index 50c02ded1d69d..2f09cb29cc950 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -5277,6 +5277,10 @@ int register_netdevice(struct net_device *dev) */ dev->hw_enc_features |= NETIF_F_SG; + /* Make NETIF_F_SG inheritable to MPLS. + */ + dev->mpls_features |= NETIF_F_SG; + ret = call_netdevice_notifiers(NETDEV_POST_INIT, dev); ret = notifier_to_errno(ret); if (ret) diff --git a/net/core/ethtool.c b/net/core/ethtool.c index 22efdaa76ebf9..4e6f63ade7416 100644 --- a/net/core/ethtool.c +++ b/net/core/ethtool.c @@ -82,6 +82,7 @@ static const char netdev_features_strings[NETDEV_FEATURE_COUNT][ETH_GSTRING_LEN] [NETIF_F_FSO_BIT] = "tx-fcoe-segmentation", [NETIF_F_GSO_GRE_BIT] = "tx-gre-segmentation", [NETIF_F_GSO_UDP_TUNNEL_BIT] = "tx-udp_tnl-segmentation", + [NETIF_F_GSO_MPLS_BIT] = "tx-mpls-segmentation", [NETIF_F_FCOE_CRC_BIT] = "tx-checksum-fcoe-crc", [NETIF_F_SCTP_CSUM_BIT] = "tx-checksum-sctp", diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c index d01be2a3ae531..b05ae96aec444 100644 --- a/net/ipv4/af_inet.c +++ b/net/ipv4/af_inet.c @@ -1295,6 +1295,7 @@ static struct sk_buff *inet_gso_segment(struct sk_buff *skb, SKB_GSO_GRE | SKB_GSO_TCPV6 | SKB_GSO_UDP_TUNNEL | + SKB_GSO_MPLS | 0))) goto out; diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index d87ce72ca8aad..ba4186e1dca98 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -2917,6 +2917,7 @@ struct sk_buff *tcp_tso_segment(struct sk_buff *skb, SKB_GSO_TCP_ECN | SKB_GSO_TCPV6 | SKB_GSO_GRE | + SKB_GSO_MPLS | SKB_GSO_UDP_TUNNEL | 0) || !(type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6)))) diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index 0bf5d399a03c1..aa5eff46d1374 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -2381,7 +2381,7 @@ struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb, if (unlikely(type & ~(SKB_GSO_UDP | SKB_GSO_DODGY | SKB_GSO_UDP_TUNNEL | - SKB_GSO_GRE) || + SKB_GSO_GRE | SKB_GSO_MPLS) || !(type & (SKB_GSO_UDP)))) goto out; diff --git a/net/ipv6/ip6_offload.c b/net/ipv6/ip6_offload.c index 71b766ee821d6..a263b990ee11d 100644 --- a/net/ipv6/ip6_offload.c +++ b/net/ipv6/ip6_offload.c @@ -98,6 +98,7 @@ static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb, SKB_GSO_TCP_ECN | SKB_GSO_GRE | SKB_GSO_UDP_TUNNEL | + SKB_GSO_MPLS | SKB_GSO_TCPV6 | 0))) goto out; diff --git a/net/ipv6/udp_offload.c b/net/ipv6/udp_offload.c index 3bb3a891a4241..76d401a93c7a3 100644 --- a/net/ipv6/udp_offload.c +++ b/net/ipv6/udp_offload.c @@ -63,7 +63,8 @@ static struct sk_buff *udp6_ufo_fragment(struct sk_buff *skb, if (unlikely(type & ~(SKB_GSO_UDP | SKB_GSO_DODGY | SKB_GSO_UDP_TUNNEL | - SKB_GSO_GRE) || + SKB_GSO_GRE | + SKB_GSO_MPLS) || !(type & (SKB_GSO_UDP)))) goto out; diff --git a/net/mpls/Kconfig b/net/mpls/Kconfig new file mode 100644 index 0000000000000..37421db889652 --- /dev/null +++ b/net/mpls/Kconfig @@ -0,0 +1,9 @@ +# +# MPLS configuration +# +config NET_MPLS_GSO + tristate "MPLS: GSO support" + help + This is helper module to allow segmentation of non-MPLS GSO packets + that have had MPLS stack entries pushed onto them and thus + become MPLS GSO packets. diff --git a/net/mpls/Makefile b/net/mpls/Makefile new file mode 100644 index 0000000000000..0a3c171be5374 --- /dev/null +++ b/net/mpls/Makefile @@ -0,0 +1,4 @@ +# +# Makefile for MPLS. +# +obj-y += mpls_gso.o diff --git a/net/mpls/mpls_gso.c b/net/mpls/mpls_gso.c new file mode 100644 index 0000000000000..1bec1219ab815 --- /dev/null +++ b/net/mpls/mpls_gso.c @@ -0,0 +1,108 @@ +/* + * MPLS GSO Support + * + * Authors: Simon Horman (horms@verge.net.au) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + * + * Based on: GSO portions of net/ipv4/gre.c + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include +#include +#include +#include +#include + +static struct sk_buff *mpls_gso_segment(struct sk_buff *skb, + netdev_features_t features) +{ + struct sk_buff *segs = ERR_PTR(-EINVAL); + netdev_features_t mpls_features; + __be16 mpls_protocol; + + if (unlikely(skb_shinfo(skb)->gso_type & + ~(SKB_GSO_TCPV4 | + SKB_GSO_TCPV6 | + SKB_GSO_UDP | + SKB_GSO_DODGY | + SKB_GSO_TCP_ECN | + SKB_GSO_GRE | + SKB_GSO_MPLS))) + goto out; + + /* Setup inner SKB. */ + mpls_protocol = skb->protocol; + skb->protocol = skb->inner_protocol; + + /* Push back the mac header that skb_mac_gso_segment() has pulled. + * It will be re-pulled by the call to skb_mac_gso_segment() below + */ + __skb_push(skb, skb->mac_len); + + /* Segment inner packet. */ + mpls_features = skb->dev->mpls_features & netif_skb_features(skb); + segs = skb_mac_gso_segment(skb, mpls_features); + + + /* Restore outer protocol. */ + skb->protocol = mpls_protocol; + + /* Re-pull the mac header that the call to skb_mac_gso_segment() + * above pulled. It will be re-pushed after returning + * skb_mac_gso_segment(), an indirect caller of this function. + */ + __skb_push(skb, skb->data - skb_mac_header(skb)); + +out: + return segs; +} + +static int mpls_gso_send_check(struct sk_buff *skb) +{ + return 0; +} + +static struct packet_offload mpls_mc_offload = { + .type = cpu_to_be16(ETH_P_MPLS_MC), + .callbacks = { + .gso_send_check = mpls_gso_send_check, + .gso_segment = mpls_gso_segment, + }, +}; + +static struct packet_offload mpls_uc_offload = { + .type = cpu_to_be16(ETH_P_MPLS_UC), + .callbacks = { + .gso_send_check = mpls_gso_send_check, + .gso_segment = mpls_gso_segment, + }, +}; + +static int __init mpls_gso_init(void) +{ + pr_info("MPLS GSO support\n"); + + dev_add_offload(&mpls_uc_offload); + dev_add_offload(&mpls_mc_offload); + + return 0; +} + +static void __exit mpls_gso_exit(void) +{ + dev_remove_offload(&mpls_uc_offload); + dev_remove_offload(&mpls_mc_offload); +} + +module_init(mpls_gso_init); +module_exit(mpls_gso_exit); + +MODULE_DESCRIPTION("MPLS GSO support"); +MODULE_AUTHOR("Simon Horman (horms@verge.net.au)"); +MODULE_LICENSE("GPL");