Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

Daniel Borkmann says:

====================
pull-request: bpf-next 2018-08-13

The following pull-request contains BPF updates for your *net-next* tree.

The main changes are:

1) Add driver XDP support for veth. This can be used in conjunction with
   redirect of another XDP program e.g. sitting on NIC so the xdp_frame
   can be forwarded to the peer veth directly without modification,
   from Toshiaki.

2) Add a new BPF map type REUSEPORT_SOCKARRAY and prog type SK_REUSEPORT
   in order to provide more control and visibility on where a SO_REUSEPORT
   sk should be located, and the latter enables to directly select a sk
   from the bpf map. This also enables map-in-map for application migration
   use cases, from Martin.

3) Add a new BPF helper bpf_skb_ancestor_cgroup_id() that returns the id
   of cgroup v2 that is the ancestor of the cgroup associated with the
   skb at the ancestor_level, from Andrey.

4) Implement BPF fs map pretty-print support based on BTF data for regular
   hash table and LRU map, from Yonghong.

5) Decouple the ability to attach BTF for a map from the key and value
   pretty-printer in BPF fs, and enable further support of BTF for maps for
   percpu and LPM trie, from Daniel.

6) Implement a better BPF sample of using XDP's CPU redirect feature for
   load balancing SKB processing to remote CPU. The sample implements the
   same XDP load balancing as Suricata does which is symmetric hash based
   on IP and L4 protocol, from Jesper.

7) Revert adding NULL pointer check with WARN_ON_ONCE() in __xdp_return()'s
   critical path as it is ensured that the allocator is present, from Björn.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

samples/bpf/hash_func01.h

@@ -0,0 +1,55 @@
+/* SPDX-License-Identifier: LGPL-2.1
+ *
+ * Based on Paul Hsieh's (LGPG 2.1) hash function
+ * From: http://www.azillionmonkeys.com/qed/hash.html
+ */
+
+#define get16bits(d) (*((const __u16 *) (d)))
+
+static __always_inline
+__u32 SuperFastHash (const char *data, int len, __u32 initval) {
+	__u32 hash = initval;
+	__u32 tmp;
+	int rem;
+
+	if (len <= 0 || data == NULL) return 0;
+
+	rem = len & 3;
+	len >>= 2;
+
+	/* Main loop */
+#pragma clang loop unroll(full)
+	for (;len > 0; len--) {
+		hash  += get16bits (data);
+		tmp    = (get16bits (data+2) << 11) ^ hash;
+		hash   = (hash << 16) ^ tmp;
+		data  += 2*sizeof (__u16);
+		hash  += hash >> 11;
+	}
+
+	/* Handle end cases */
+	switch (rem) {
+        case 3: hash += get16bits (data);
+                hash ^= hash << 16;
+                hash ^= ((signed char)data[sizeof (__u16)]) << 18;
+                hash += hash >> 11;
+                break;
+        case 2: hash += get16bits (data);
+                hash ^= hash << 11;
+                hash += hash >> 17;
+                break;
+        case 1: hash += (signed char)*data;
+                hash ^= hash << 10;
+                hash += hash >> 1;
+	}
+
+	/* Force "avalanching" of final 127 bits */
+	hash ^= hash << 3;
+	hash += hash >> 5;
+	hash ^= hash << 4;
+	hash += hash >> 17;
+	hash ^= hash << 25;
+	hash += hash >> 6;
+
+	return hash;
+}

samples/bpf/xdp_redirect_cpu_kern.c

@@ -13,6 +13,7 @@
 
 #include <uapi/linux/bpf.h>
 #include "bpf_helpers.h"
+#include "hash_func01.h"
 
 #define MAX_CPUS 64 /* WARNING - sync with _user.c */
 
@@ -461,6 +462,108 @@ int  xdp_prognum4_ddos_filter_pktgen(struct xdp_md *ctx)
 	return bpf_redirect_map(&cpu_map, cpu_dest, 0);
 }
 
+/* Hashing initval */
+#define INITVAL 15485863
+
+static __always_inline
+u32 get_ipv4_hash_ip_pair(struct xdp_md *ctx, u64 nh_off)
+{
+	void *data_end = (void *)(long)ctx->data_end;
+	void *data     = (void *)(long)ctx->data;
+	struct iphdr *iph = data + nh_off;
+	u32 cpu_hash;
+
+	if (iph + 1 > data_end)
+		return 0;
+
+	cpu_hash = iph->saddr + iph->daddr;
+	cpu_hash = SuperFastHash((char *)&cpu_hash, 4, INITVAL + iph->protocol);
+
+	return cpu_hash;
+}
+
+static __always_inline
+u32 get_ipv6_hash_ip_pair(struct xdp_md *ctx, u64 nh_off)
+{
+	void *data_end = (void *)(long)ctx->data_end;
+	void *data     = (void *)(long)ctx->data;
+	struct ipv6hdr *ip6h = data + nh_off;
+	u32 cpu_hash;
+
+	if (ip6h + 1 > data_end)
+		return 0;
+
+	cpu_hash  = ip6h->saddr.s6_addr32[0] + ip6h->daddr.s6_addr32[0];
+	cpu_hash += ip6h->saddr.s6_addr32[1] + ip6h->daddr.s6_addr32[1];
+	cpu_hash += ip6h->saddr.s6_addr32[2] + ip6h->daddr.s6_addr32[2];
+	cpu_hash += ip6h->saddr.s6_addr32[3] + ip6h->daddr.s6_addr32[3];
+	cpu_hash = SuperFastHash((char *)&cpu_hash, 4, INITVAL + ip6h->nexthdr);
+
+	return cpu_hash;
+}
+
+/* Load-Balance traffic based on hashing IP-addrs + L4-proto.  The
+ * hashing scheme is symmetric, meaning swapping IP src/dest still hit
+ * same CPU.
+ */
+SEC("xdp_cpu_map5_lb_hash_ip_pairs")
+int  xdp_prognum5_lb_hash_ip_pairs(struct xdp_md *ctx)
+{
+	void *data_end = (void *)(long)ctx->data_end;
+	void *data     = (void *)(long)ctx->data;
+	struct ethhdr *eth = data;
+	u8 ip_proto = IPPROTO_UDP;
+	struct datarec *rec;
+	u16 eth_proto = 0;
+	u64 l3_offset = 0;
+	u32 cpu_dest = 0;
+	u32 cpu_idx = 0;
+	u32 *cpu_lookup;
+	u32 *cpu_max;
+	u32 cpu_hash;
+	u32 key = 0;
+
+	/* Count RX packet in map */
+	rec = bpf_map_lookup_elem(&rx_cnt, &key);
+	if (!rec)
+		return XDP_ABORTED;
+	rec->processed++;
+
+	cpu_max = bpf_map_lookup_elem(&cpus_count, &key);
+	if (!cpu_max)
+		return XDP_ABORTED;
+
+	if (!(parse_eth(eth, data_end, &eth_proto, &l3_offset)))
+		return XDP_PASS; /* Just skip */
+
+	/* Hash for IPv4 and IPv6 */
+	switch (eth_proto) {
+	case ETH_P_IP:
+		cpu_hash = get_ipv4_hash_ip_pair(ctx, l3_offset);
+		break;
+	case ETH_P_IPV6:
+		cpu_hash = get_ipv6_hash_ip_pair(ctx, l3_offset);
+		break;
+	case ETH_P_ARP: /* ARP packet handled on CPU idx 0 */
+	default:
+		cpu_hash = 0;
+	}
+
+	/* Choose CPU based on hash */
+	cpu_idx = cpu_hash % *cpu_max;
+
+	cpu_lookup = bpf_map_lookup_elem(&cpus_available, &cpu_idx);
+	if (!cpu_lookup)
+		return XDP_ABORTED;
+	cpu_dest = *cpu_lookup;
+
+	if (cpu_dest >= MAX_CPUS) {
+		rec->issue++;
+		return XDP_ABORTED;
+	}
+
+	return bpf_redirect_map(&cpu_map, cpu_dest, 0);
+}
 
 char _license[] SEC("license") = "GPL";
 

samples/bpf/xdp_redirect_cpu_user.c

@@ -22,7 +22,7 @@ static const char *__doc__ =
 #define MAX_CPUS 64 /* WARNING - sync with _kern.c */
 
 /* How many xdp_progs are defined in _kern.c */
-#define MAX_PROG 5
+#define MAX_PROG 6
 
 /* Wanted to get rid of bpf_load.h and fake-"libbpf.h" (and instead
  * use bpf/libbpf.h), but cannot as (currently) needed for XDP
@@ -567,7 +567,7 @@ int main(int argc, char **argv)
 	int added_cpus = 0;
 	int longindex = 0;
 	int interval = 2;
-	int prog_num = 0;
+	int prog_num = 5;
 	int add_cpu = -1;
 	__u32 qsize;
 	int opt;