tc, bpf, examples: further bpf_api improvements

Add a couple of improvements to tc's BPF api, that facilitate program
development.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

diff --git a/examples/bpf/bpf_cyclic.c b/examples/bpf/bpf_cyclic.c
index c66cbecce054f45c5d05b189ffcc080970fb70d0..36745a3c8a9228782bc12d35e0c073998449bb58 100644 (file)
--- a/examples/bpf/bpf_cyclic.c
+++ b/examples/bpf/bpf_cyclic.c
@@ -11,9 +11,7 @@ BPF_PROG_ARRAY(jmp_tc, JMP_MAP_ID, PIN_OBJECT_NS, 1);
 __section_tail(JMP_MAP_ID, 0)
 int cls_loop(struct __sk_buff *skb)
 {
-       char fmt[] = "cb: %u\n";
-
-       trace_printk(fmt, sizeof(fmt), skb->cb[0]++);
+       printt("cb: %u\n", skb->cb[0]++);
        tail_call(skb, &jmp_tc, 0);
 
        skb->tc_classid = TC_H_MAKE(1, 42);

diff --git a/examples/bpf/bpf_graft.c b/examples/bpf/bpf_graft.c
index f48fd0288543ac1a0cc92c9efc246e3bff71f5d9..20784ff4a5f74e221d270ac576a3c8f7ed12b963 100644 (file)
--- a/examples/bpf/bpf_graft.c
+++ b/examples/bpf/bpf_graft.c
@@ -38,29 +38,22 @@ BPF_PROG_ARRAY(jmp_tc, 0, PIN_GLOBAL_NS, 1);
 __section("aaa")
 int cls_aaa(struct __sk_buff *skb)
 {
-       char fmt[] = "aaa\n";
-
-       trace_printk(fmt, sizeof(fmt));
+       printt("aaa\n");
        return TC_H_MAKE(1, 42);
 }
 
 __section("bbb")
 int cls_bbb(struct __sk_buff *skb)
 {
-       char fmt[] = "bbb\n";
-
-       trace_printk(fmt, sizeof(fmt));
+       printt("bbb\n");
        return TC_H_MAKE(1, 43);
 }
 
 __section_cls_entry
 int cls_entry(struct __sk_buff *skb)
 {
-       char fmt[] = "fallthrough\n";
-
        tail_call(skb, &jmp_tc, 0);
-       trace_printk(fmt, sizeof(fmt));
-
+       printt("fallthrough\n");
        return BPF_H_DEFAULT;
 }
 

diff --git a/examples/bpf/bpf_prog.c b/examples/bpf/bpf_prog.c
index 47280492591dbc4e91ff64eaf71685a22cbacc48..f15e876c20a4f147804cf35997ce1411d6688907 100644 (file)
--- a/examples/bpf/bpf_prog.c
+++ b/examples/bpf/bpf_prog.c
@@ -233,7 +233,7 @@ struct flow_keys {
        __u8 ip_proto;
 };
 
-static inline int flow_ports_offset(__u8 ip_proto)
+static __inline__ int flow_ports_offset(__u8 ip_proto)
 {
        switch (ip_proto) {
        case IPPROTO_TCP:
@@ -249,14 +249,14 @@ static inline int flow_ports_offset(__u8 ip_proto)
        }
 }
 
-static inline bool flow_is_frag(struct __sk_buff *skb, int nh_off)
+static __inline__ bool flow_is_frag(struct __sk_buff *skb, int nh_off)
 {
        return !!(load_half(skb, nh_off + offsetof(struct iphdr, frag_off)) &
                  (IP_MF | IP_OFFSET));
 }
 
-static inline int flow_parse_ipv4(struct __sk_buff *skb, int nh_off,
-                                 __u8 *ip_proto, struct flow_keys *flow)
+static __inline__ int flow_parse_ipv4(struct __sk_buff *skb, int nh_off,
+                                     __u8 *ip_proto, struct flow_keys *flow)
 {
        __u8 ip_ver_len;
 
@@ -279,7 +279,7 @@ static inline int flow_parse_ipv4(struct __sk_buff *skb, int nh_off,
        return nh_off;
 }
 
-static inline __u32 flow_addr_hash_ipv6(struct __sk_buff *skb, int off)
+static __inline__ __u32 flow_addr_hash_ipv6(struct __sk_buff *skb, int off)
 {
        __u32 w0 = load_word(skb, off);
        __u32 w1 = load_word(skb, off + sizeof(w0));
@@ -289,8 +289,8 @@ static inline __u32 flow_addr_hash_ipv6(struct __sk_buff *skb, int off)
        return w0 ^ w1 ^ w2 ^ w3;
 }
 
-static inline int flow_parse_ipv6(struct __sk_buff *skb, int nh_off,
-                                 __u8 *ip_proto, struct flow_keys *flow)
+static __inline__ int flow_parse_ipv6(struct __sk_buff *skb, int nh_off,
+                                     __u8 *ip_proto, struct flow_keys *flow)
 {
        *ip_proto = load_byte(skb, nh_off + offsetof(struct ipv6hdr, nexthdr));
 
@@ -300,8 +300,8 @@ static inline int flow_parse_ipv6(struct __sk_buff *skb, int nh_off,
        return nh_off + sizeof(struct ipv6hdr);
 }
 
-static inline bool flow_dissector(struct __sk_buff *skb,
-                                 struct flow_keys *flow)
+static __inline__ bool flow_dissector(struct __sk_buff *skb,
+                                     struct flow_keys *flow)
 {
        int poff, nh_off = BPF_LL_OFF + ETH_HLEN;
        __be16 proto = skb->protocol;
@@ -381,8 +381,8 @@ static inline bool flow_dissector(struct __sk_buff *skb,
        return true;
 }
 
-static inline void cls_update_proto_map(const struct __sk_buff *skb,
-                                       const struct flow_keys *flow)
+static __inline__ void cls_update_proto_map(const struct __sk_buff *skb,
+                                           const struct flow_keys *flow)
 {
        uint8_t proto = flow->ip_proto;
        struct count_tuple *ct, _ct;
@@ -401,7 +401,7 @@ static inline void cls_update_proto_map(const struct __sk_buff *skb,
        map_update_elem(&map_proto, &proto, &_ct, BPF_ANY);
 }
 
-static inline void cls_update_queue_map(const struct __sk_buff *skb)
+static __inline__ void cls_update_queue_map(const struct __sk_buff *skb)
 {
        uint32_t queue = skb->queue_mapping;
        struct count_queue *cq, _cq;
@@ -453,7 +453,7 @@ int cls_main(struct __sk_buff *skb)
        return flow.ip_proto;
 }
 
-static inline void act_update_drop_map(void)
+static __inline__ void act_update_drop_map(void)
 {
        uint32_t *count, cpu = get_smp_processor_id();
 

diff --git a/examples/bpf/bpf_shared.c b/examples/bpf/bpf_shared.c
index accc0adf4a0eec519c9a6b660891c30f2d0642de..7fe9ef30fd6494fb4a097352536dab1de6b8a670 100644 (file)
--- a/examples/bpf/bpf_shared.c
+++ b/examples/bpf/bpf_shared.c
@@ -35,12 +35,11 @@ int emain(struct __sk_buff *skb)
 __section("ingress")
 int imain(struct __sk_buff *skb)
 {
-       char fmt[] = "map val: %d\n";
        int key = 0, *val;
 
        val = map_lookup_elem(&map_sh, &key);
        if (val)
-               trace_printk(fmt, sizeof(fmt), *val);
+               printt("map val: %d\n", *val);
 
        return BPF_H_DEFAULT;
 }

diff --git a/examples/bpf/bpf_tailcall.c b/examples/bpf/bpf_tailcall.c
index 040790d0e7cfcac42c63aa481c6c0370b34bd830..f545430f7535fcf91c732d35b8dfd9574d4a61a5 100644 (file)
--- a/examples/bpf/bpf_tailcall.c
+++ b/examples/bpf/bpf_tailcall.c
@@ -34,12 +34,11 @@ BPF_ARRAY4(map_sh, 0, PIN_OBJECT_NS, 1);
 __section_tail(FOO, ENTRY_0)
 int cls_case1(struct __sk_buff *skb)
 {
-       char fmt[] = "case1: map-val: %d from:%u\n";
        int key = 0, *val;
 
        val = map_lookup_elem(&map_sh, &key);
        if (val)
-               trace_printk(fmt, sizeof(fmt), *val, skb->cb[0]);
+               printt("case1: map-val: %d from:%u\n", *val, skb->cb[0]);
 
        skb->cb[0] = ENTRY_0;
        tail_call(skb, &jmp_ex, ENTRY_0);
@@ -50,12 +49,11 @@ int cls_case1(struct __sk_buff *skb)
 __section_tail(FOO, ENTRY_1)
 int cls_case2(struct __sk_buff *skb)
 {
-       char fmt[] = "case2: map-val: %d from:%u\n";
        int key = 0, *val;
 
        val = map_lookup_elem(&map_sh, &key);
        if (val)
-               trace_printk(fmt, sizeof(fmt), *val, skb->cb[0]);
+               printt("case2: map-val: %d from:%u\n", *val, skb->cb[0]);
 
        skb->cb[0] = ENTRY_1;
        tail_call(skb, &jmp_tc, ENTRY_0);
@@ -66,12 +64,11 @@ int cls_case2(struct __sk_buff *skb)
 __section_tail(BAR, ENTRY_0)
 int cls_exit(struct __sk_buff *skb)
 {
-       char fmt[] = "exit: map-val: %d from:%u\n";
        int key = 0, *val;
 
        val = map_lookup_elem(&map_sh, &key);
        if (val)
-               trace_printk(fmt, sizeof(fmt), *val, skb->cb[0]);
+               printt("exit: map-val: %d from:%u\n", *val, skb->cb[0]);
 
        /* Termination point. */
        return BPF_H_DEFAULT;
@@ -80,7 +77,6 @@ int cls_exit(struct __sk_buff *skb)
 __section_cls_entry
 int cls_entry(struct __sk_buff *skb)
 {
-       char fmt[] = "fallthrough\n";
        int key = 0, *val;
 
        /* For transferring state, we can use skb->cb[0] ... skb->cb[4]. */
@@ -92,7 +88,7 @@ int cls_entry(struct __sk_buff *skb)
                tail_call(skb, &jmp_tc, skb->hash & (MAX_JMP_SIZE - 1));
        }
 
-       trace_printk(fmt, sizeof(fmt));
+       printt("fallthrough\n");
        return BPF_H_DEFAULT;
 }
 

diff --git a/include/bpf_api.h b/include/bpf_api.h
index 0666a312e35ce75f5d49d645ee99c8bda66ab260..4b16d25c3cbd3282429ce4db99bc21c19a533c71 100644 (file)
--- a/include/bpf_api.h
+++ b/include/bpf_api.h
@@ -56,6 +56,10 @@
 # define ntohl(X)              __constant_ntohl((X))
 #endif
 
+#ifndef __inline__
+# define __inline__            __attribute__((always_inline))
+#endif
+
 /** Section helper macros. */
 
 #ifndef __section
@@ -146,7 +150,7 @@
 # define BPF_H_DEFAULT -1
 #endif
 
-/** BPF helper functions for tc. */
+/** BPF helper functions for tc. Individual flags are in linux/bpf.h */
 
 #ifndef BPF_FUNC
 # define BPF_FUNC(NAME, ...)                                           \
@@ -163,8 +167,22 @@ static int BPF_FUNC(map_delete_elem, void *map, const void *key);
 static uint64_t BPF_FUNC(ktime_get_ns);
 
 /* Debugging */
+
+/* FIXME: __attribute__ ((format(printf, 1, 3))) not possible unless
+ * llvm bug https://llvm.org/bugs/show_bug.cgi?id=26243 gets resolved.
+ * It would require ____fmt to be made const, which generates a reloc
+ * entry (non-map).
+ */
 static void BPF_FUNC(trace_printk, const char *fmt, int fmt_size, ...);
 
+#ifndef printt
+# define printt(fmt, ...)                                              \
+       ({                                                              \
+               char ____fmt[] = fmt;                                   \
+               trace_printk(____fmt, sizeof(____fmt), ##__VA_ARGS__);  \
+       })
+#endif
+
 /* Random numbers */
 static uint32_t BPF_FUNC(get_prandom_u32);
 
@@ -185,12 +203,11 @@ static int BPF_FUNC(clone_redirect, struct __sk_buff *skb, int ifindex,
                    uint32_t flags);
 
 /* Packet manipulation */
-#define BPF_PSEUDO_HDR                 0x10
-#define BPF_HAS_PSEUDO_HDR(flags)      ((flags) & BPF_PSEUDO_HDR)
-#define BPF_HDR_FIELD_SIZE(flags)      ((flags) & 0x0f)
-
+static int BPF_FUNC(skb_load_bytes, struct __sk_buff *skb, uint32_t off,
+                   void *to, uint32_t len);
 static int BPF_FUNC(skb_store_bytes, struct __sk_buff *skb, uint32_t off,
-                   void *from, uint32_t len, uint32_t flags);
+                   const void *from, uint32_t len, uint32_t flags);
+
 static int BPF_FUNC(l3_csum_replace, struct __sk_buff *skb, uint32_t off,
                    uint32_t from, uint32_t to, uint32_t flags);
 static int BPF_FUNC(l4_csum_replace, struct __sk_buff *skb, uint32_t off,
@@ -205,14 +222,37 @@ static int BPF_FUNC(skb_vlan_pop, struct __sk_buff *skb);
 static int BPF_FUNC(skb_get_tunnel_key, struct __sk_buff *skb,
                    struct bpf_tunnel_key *to, uint32_t size, uint32_t flags);
 static int BPF_FUNC(skb_set_tunnel_key, struct __sk_buff *skb,
-                   struct bpf_tunnel_key *from, uint32_t size, uint32_t flags);
+                   const struct bpf_tunnel_key *from, uint32_t size,
+                   uint32_t flags);
 
-/** LLVM built-ins */
+/** LLVM built-ins, mem*() routines work for constant size */
 
 #ifndef lock_xadd
 # define lock_xadd(ptr, val)   ((void) __sync_fetch_and_add(ptr, val))
 #endif
 
+#ifndef memset
+# define memset(s, c, n)       __builtin_memset((s), (c), (n))
+#endif
+
+#ifndef memcpy
+# define memcpy(d, s, n)       __builtin_memcpy((d), (s), (n))
+#endif
+
+#ifndef memmove
+# define memmove(d, s, n)      __builtin_memmove((d), (s), (n))
+#endif
+
+/* FIXME: __builtin_memcmp() is not yet fully useable unless llvm bug
+ * https://llvm.org/bugs/show_bug.cgi?id=26218 gets resolved. Also
+ * this one would generate a reloc entry (non-map), otherwise.
+ */
+#if 0
+#ifndef memcmp
+# define memcmp(a, b, n)       __builtin_memcmp((a), (b), (n))
+#endif
+#endif
+
 unsigned long long load_byte(void *skb, unsigned long long off)
        asm ("llvm.bpf.load.byte");