From dac06b32c705dc8824479b03eee826b4f6615ab2 Mon Sep 17 00:00:00 2001 From: Alexander Lobakin Date: Sun, 14 Mar 2021 11:11:00 +0000 Subject: [PATCH 1/6] flow_dissector: constify bpf_flow_dissector's data pointers BPF Flow dissection programs are read-only and don't touch input buffers. Mark 'data' and 'data_end' in struct bpf_flow_dissector as const in preparation for global input constifying. Signed-off-by: Alexander Lobakin Signed-off-by: David S. Miller --- include/net/flow_dissector.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/include/net/flow_dissector.h b/include/net/flow_dissector.h index cc10b10dc3a1..bf00e71816ed 100644 --- a/include/net/flow_dissector.h +++ b/include/net/flow_dissector.h @@ -368,8 +368,8 @@ static inline void *skb_flow_dissector_target(struct flow_dissector *flow_dissec struct bpf_flow_dissector { struct bpf_flow_keys *flow_keys; const struct sk_buff *skb; - void *data; - void *data_end; + const void *data; + const void *data_end; }; static inline void From e3305138da47f0ae2241e5daa18af276e1e54457 Mon Sep 17 00:00:00 2001 From: Alexander Lobakin Date: Sun, 14 Mar 2021 11:11:14 +0000 Subject: [PATCH 2/6] skbuff: make __skb_header_pointer()'s data argument const The function never modifies the input buffer, so 'data' argument can be marked as const. This implies one harmless cast-away. Signed-off-by: Alexander Lobakin Signed-off-by: David S. Miller --- include/linux/skbuff.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 483e89348f78..d6ea3dc3eddb 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -3678,11 +3678,11 @@ __wsum skb_checksum(const struct sk_buff *skb, int offset, int len, __wsum csum); static inline void * __must_check -__skb_header_pointer(const struct sk_buff *skb, int offset, - int len, void *data, int hlen, void *buffer) +__skb_header_pointer(const struct sk_buff *skb, int offset, int len, + const void *data, int hlen, void *buffer) { if (hlen - offset >= len) - return data + offset; + return (void *)data + offset; if (!skb || skb_copy_bits(skb, offset, buffer, len) < 0) From f96533cded173b3b019001a505a746c3cd8fc323 Mon Sep 17 00:00:00 2001 From: Alexander Lobakin Date: Sun, 14 Mar 2021 11:11:23 +0000 Subject: [PATCH 3/6] flow_dissector: constify raw input data argument Flow Dissector code never modifies the input buffer, neither skb nor raw data. Make 'data' argument const for all of the Flow dissector's functions. Signed-off-by: Alexander Lobakin Signed-off-by: David S. Miller --- include/linux/skbuff.h | 15 ++++++------- include/net/flow_dissector.h | 2 +- net/core/flow_dissector.c | 41 +++++++++++++++++++----------------- 3 files changed, 30 insertions(+), 28 deletions(-) diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index d6ea3dc3eddb..46c61e127e9f 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -1292,10 +1292,10 @@ __skb_set_sw_hash(struct sk_buff *skb, __u32 hash, bool is_l4) void __skb_get_hash(struct sk_buff *skb); u32 __skb_get_hash_symmetric(const struct sk_buff *skb); u32 skb_get_poff(const struct sk_buff *skb); -u32 __skb_get_poff(const struct sk_buff *skb, void *data, +u32 __skb_get_poff(const struct sk_buff *skb, const void *data, const struct flow_keys_basic *keys, int hlen); __be32 __skb_flow_get_ports(const struct sk_buff *skb, int thoff, u8 ip_proto, - void *data, int hlen_proto); + const void *data, int hlen_proto); static inline __be32 skb_flow_get_ports(const struct sk_buff *skb, int thoff, u8 ip_proto) @@ -1314,9 +1314,8 @@ bool bpf_flow_dissect(struct bpf_prog *prog, struct bpf_flow_dissector *ctx, bool __skb_flow_dissect(const struct net *net, const struct sk_buff *skb, struct flow_dissector *flow_dissector, - void *target_container, - void *data, __be16 proto, int nhoff, int hlen, - unsigned int flags); + void *target_container, const void *data, + __be16 proto, int nhoff, int hlen, unsigned int flags); static inline bool skb_flow_dissect(const struct sk_buff *skb, struct flow_dissector *flow_dissector, @@ -1338,9 +1337,9 @@ static inline bool skb_flow_dissect_flow_keys(const struct sk_buff *skb, static inline bool skb_flow_dissect_flow_keys_basic(const struct net *net, const struct sk_buff *skb, - struct flow_keys_basic *flow, void *data, - __be16 proto, int nhoff, int hlen, - unsigned int flags) + struct flow_keys_basic *flow, + const void *data, __be16 proto, + int nhoff, int hlen, unsigned int flags) { memset(flow, 0, sizeof(*flow)); return __skb_flow_dissect(net, skb, &flow_keys_basic_dissector, flow, diff --git a/include/net/flow_dissector.h b/include/net/flow_dissector.h index bf00e71816ed..ffd386ea0dbb 100644 --- a/include/net/flow_dissector.h +++ b/include/net/flow_dissector.h @@ -350,7 +350,7 @@ static inline bool flow_keys_have_l4(const struct flow_keys *keys) u32 flow_hash_from_keys(struct flow_keys *keys); void skb_flow_get_icmp_tci(const struct sk_buff *skb, struct flow_dissector_key_icmp *key_icmp, - void *data, int thoff, int hlen); + const void *data, int thoff, int hlen); static inline bool dissector_uses_key(const struct flow_dissector *flow_dissector, enum flow_dissector_key_id key_id) diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c index 2ef2224b3bff..2ed380d096ce 100644 --- a/net/core/flow_dissector.c +++ b/net/core/flow_dissector.c @@ -114,7 +114,7 @@ int flow_dissector_bpf_prog_attach_check(struct net *net, * is the protocol port offset returned from proto_ports_offset */ __be32 __skb_flow_get_ports(const struct sk_buff *skb, int thoff, u8 ip_proto, - void *data, int hlen) + const void *data, int hlen) { int poff = proto_ports_offset(ip_proto); @@ -161,7 +161,7 @@ static bool icmp_has_id(u8 type) */ void skb_flow_get_icmp_tci(const struct sk_buff *skb, struct flow_dissector_key_icmp *key_icmp, - void *data, int thoff, int hlen) + const void *data, int thoff, int hlen) { struct icmphdr *ih, _ih; @@ -187,8 +187,8 @@ EXPORT_SYMBOL(skb_flow_get_icmp_tci); */ static void __skb_flow_dissect_icmp(const struct sk_buff *skb, struct flow_dissector *flow_dissector, - void *target_container, - void *data, int thoff, int hlen) + void *target_container, const void *data, + int thoff, int hlen) { struct flow_dissector_key_icmp *key_icmp; @@ -409,8 +409,8 @@ EXPORT_SYMBOL(skb_flow_dissect_hash); static enum flow_dissect_ret __skb_flow_dissect_mpls(const struct sk_buff *skb, struct flow_dissector *flow_dissector, - void *target_container, void *data, int nhoff, int hlen, - int lse_index, bool *entropy_label) + void *target_container, const void *data, int nhoff, + int hlen, int lse_index, bool *entropy_label) { struct mpls_label *hdr, _hdr; u32 entry, label, bos; @@ -467,7 +467,8 @@ __skb_flow_dissect_mpls(const struct sk_buff *skb, static enum flow_dissect_ret __skb_flow_dissect_arp(const struct sk_buff *skb, struct flow_dissector *flow_dissector, - void *target_container, void *data, int nhoff, int hlen) + void *target_container, const void *data, + int nhoff, int hlen) { struct flow_dissector_key_arp *key_arp; struct { @@ -523,7 +524,7 @@ static enum flow_dissect_ret __skb_flow_dissect_gre(const struct sk_buff *skb, struct flow_dissector_key_control *key_control, struct flow_dissector *flow_dissector, - void *target_container, void *data, + void *target_container, const void *data, __be16 *p_proto, int *p_nhoff, int *p_hlen, unsigned int flags) { @@ -663,8 +664,8 @@ __skb_flow_dissect_gre(const struct sk_buff *skb, static enum flow_dissect_ret __skb_flow_dissect_batadv(const struct sk_buff *skb, struct flow_dissector_key_control *key_control, - void *data, __be16 *p_proto, int *p_nhoff, int hlen, - unsigned int flags) + const void *data, __be16 *p_proto, int *p_nhoff, + int hlen, unsigned int flags) { struct { struct batadv_unicast_packet batadv_unicast; @@ -695,7 +696,8 @@ __skb_flow_dissect_batadv(const struct sk_buff *skb, static void __skb_flow_dissect_tcp(const struct sk_buff *skb, struct flow_dissector *flow_dissector, - void *target_container, void *data, int thoff, int hlen) + void *target_container, const void *data, + int thoff, int hlen) { struct flow_dissector_key_tcp *key_tcp; struct tcphdr *th, _th; @@ -719,8 +721,8 @@ __skb_flow_dissect_tcp(const struct sk_buff *skb, static void __skb_flow_dissect_ports(const struct sk_buff *skb, struct flow_dissector *flow_dissector, - void *target_container, void *data, int nhoff, - u8 ip_proto, int hlen) + void *target_container, const void *data, + int nhoff, u8 ip_proto, int hlen) { enum flow_dissector_key_id dissector_ports = FLOW_DISSECTOR_KEY_MAX; struct flow_dissector_key_ports *key_ports; @@ -744,7 +746,8 @@ __skb_flow_dissect_ports(const struct sk_buff *skb, static void __skb_flow_dissect_ipv4(const struct sk_buff *skb, struct flow_dissector *flow_dissector, - void *target_container, void *data, const struct iphdr *iph) + void *target_container, const void *data, + const struct iphdr *iph) { struct flow_dissector_key_ip *key_ip; @@ -761,7 +764,8 @@ __skb_flow_dissect_ipv4(const struct sk_buff *skb, static void __skb_flow_dissect_ipv6(const struct sk_buff *skb, struct flow_dissector *flow_dissector, - void *target_container, void *data, const struct ipv6hdr *iph) + void *target_container, const void *data, + const struct ipv6hdr *iph) { struct flow_dissector_key_ip *key_ip; @@ -908,9 +912,8 @@ bool bpf_flow_dissect(struct bpf_prog *prog, struct bpf_flow_dissector *ctx, bool __skb_flow_dissect(const struct net *net, const struct sk_buff *skb, struct flow_dissector *flow_dissector, - void *target_container, - void *data, __be16 proto, int nhoff, int hlen, - unsigned int flags) + void *target_container, const void *data, + __be16 proto, int nhoff, int hlen, unsigned int flags) { struct flow_dissector_key_control *key_control; struct flow_dissector_key_basic *key_basic; @@ -1642,7 +1645,7 @@ __u32 skb_get_hash_perturb(const struct sk_buff *skb, } EXPORT_SYMBOL(skb_get_hash_perturb); -u32 __skb_get_poff(const struct sk_buff *skb, void *data, +u32 __skb_get_poff(const struct sk_buff *skb, const void *data, const struct flow_keys_basic *keys, int hlen) { u32 poff = keys->control.thoff; From 805a25f3a1bdf4aafd0af412ce1e47d0cb6c7628 Mon Sep 17 00:00:00 2001 From: Alexander Lobakin Date: Sun, 14 Mar 2021 11:11:32 +0000 Subject: [PATCH 4/6] linux/etherdevice.h: misc trailing whitespace cleanup Caught by the text editor. Fix it separately from the actual changes. Signed-off-by: Alexander Lobakin Signed-off-by: David S. Miller --- include/linux/etherdevice.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/etherdevice.h b/include/linux/etherdevice.h index 2e5debc0373c..bcb2f81baafb 100644 --- a/include/linux/etherdevice.h +++ b/include/linux/etherdevice.h @@ -11,7 +11,7 @@ * Authors: Ross Biro * Fred N. van Kempen, * - * Relocated to include/linux where it belongs by Alan Cox + * Relocated to include/linux where it belongs by Alan Cox * */ #ifndef _LINUX_ETHERDEVICE_H From 59753ce8b196de60211a989c75ece8aeb0d9d57c Mon Sep 17 00:00:00 2001 From: Alexander Lobakin Date: Sun, 14 Mar 2021 11:11:41 +0000 Subject: [PATCH 5/6] ethernet: constify eth_get_headlen()'s data argument It's used only for flow dissection, which now takes constant data pointers. Signed-off-by: Alexander Lobakin Signed-off-by: David S. Miller --- include/linux/etherdevice.h | 2 +- net/ethernet/eth.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/include/linux/etherdevice.h b/include/linux/etherdevice.h index bcb2f81baafb..330345b1be54 100644 --- a/include/linux/etherdevice.h +++ b/include/linux/etherdevice.h @@ -29,7 +29,7 @@ struct device; int eth_platform_get_mac_address(struct device *dev, u8 *mac_addr); unsigned char *arch_get_platform_mac_address(void); int nvmem_get_mac_address(struct device *dev, void *addrbuf); -u32 eth_get_headlen(const struct net_device *dev, void *data, unsigned int len); +u32 eth_get_headlen(const struct net_device *dev, const void *data, u32 len); __be16 eth_type_trans(struct sk_buff *skb, struct net_device *dev); extern const struct header_ops eth_header_ops; diff --git a/net/ethernet/eth.c b/net/ethernet/eth.c index 4106373180c6..e01cf766d2c5 100644 --- a/net/ethernet/eth.c +++ b/net/ethernet/eth.c @@ -122,7 +122,7 @@ EXPORT_SYMBOL(eth_header); * Make a best effort attempt to pull the length for all of the headers for * a given frame in a linear buffer. */ -u32 eth_get_headlen(const struct net_device *dev, void *data, unsigned int len) +u32 eth_get_headlen(const struct net_device *dev, const void *data, u32 len) { const unsigned int flags = FLOW_DISSECTOR_F_PARSE_1ST_FRAG; const struct ethhdr *eth = (const struct ethhdr *)data; From d206121faf8bb2239cd970af0bd32f5203780427 Mon Sep 17 00:00:00 2001 From: Alexander Lobakin Date: Sun, 14 Mar 2021 11:11:50 +0000 Subject: [PATCH 6/6] skbuff: micro-optimize {,__}skb_header_pointer() {,__}skb_header_pointer() helpers exist mainly for preventing accesses-beyond-end of the linear data. In the vast majorify of cases, they bail out on the first condition. All code going after is mostly a fallback. Mark the most common branch as 'likely' one to move it in-line. Also, skb_copy_bits() can return negative values only when the input arguments are invalid, e.g. offset is greater than skb->len. It can be safely marked as 'unlikely' branch, assuming that hotpath code provides sane input to not fail here. These two bump the throughput with a single Flow Dissector pass on every packet (e.g. with RPS or driver that uses eth_get_headlen()) on 20 Mbps per flow/core. Signed-off-by: Alexander Lobakin Signed-off-by: David S. Miller --- include/linux/skbuff.h | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 46c61e127e9f..ecc029674ae4 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -3680,11 +3680,10 @@ static inline void * __must_check __skb_header_pointer(const struct sk_buff *skb, int offset, int len, const void *data, int hlen, void *buffer) { - if (hlen - offset >= len) + if (likely(hlen - offset >= len)) return (void *)data + offset; - if (!skb || - skb_copy_bits(skb, offset, buffer, len) < 0) + if (!skb || unlikely(skb_copy_bits(skb, offset, buffer, len) < 0)) return NULL; return buffer;