bpf.2: Place EXAMPLES section in correct location

As per section ordering rules given in man-pages(7).

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

1 files changed, 69 insertions, 69 deletions

diff --git a/man2/bpf.2 b/man2/bpf.2
index f14b79cb17..86f3c3a40d 100644
--- a/man2/bpf.2
+++ b/man2/bpf.2
@@ -971,75 +971,6 @@ ioctl(event_fd, PERF_EVENT_IOC_SET_BPF, prog_fd);
 .in
 .\"
 .\"
-.SH EXAMPLES
-.EX
-/* bpf+sockets example:
- * 1. create array map of 256 elements
- * 2. load program that counts number of packets received
- *    r0 = skb->data[ETH_HLEN + offsetof(struct iphdr, protocol)]
- *    map[r0]++
- * 3. attach prog_fd to raw socket via setsockopt()
- * 4. print number of received TCP/UDP packets every second
- */
-int
-main(int argc, char **argv)
-{
-    int sock, map_fd, prog_fd, key;
-    long long value = 0, tcp_cnt, udp_cnt;
-
-    map_fd = bpf_create_map(BPF_MAP_TYPE_ARRAY, sizeof(key),
-                            sizeof(value), 256);
-    if (map_fd < 0) {
-        printf("failed to create map \(aq%s\(aq\en", strerror(errno));
-        /* likely not run as root */
-        return 1;
-    }
-
-    struct bpf_insn prog[] = {
-        BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),        /* r6 = r1 */
-        BPF_LD_ABS(BPF_B, ETH_HLEN + offsetof(struct iphdr, protocol)),
-                                /* r0 = ip->proto */
-        BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_0, -4),
-                                /* *(u32 *)(fp - 4) = r0 */
-        BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),       /* r2 = fp */
-        BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -4),      /* r2 = r2 - 4 */
-        BPF_LD_MAP_FD(BPF_REG_1, map_fd),           /* r1 = map_fd */
-        BPF_CALL_FUNC(BPF_FUNC_map_lookup_elem),
-                                /* r0 = map_lookup(r1, r2) */
-        BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 2),
-                                /* if (r0 == 0) goto pc+2 */
-        BPF_MOV64_IMM(BPF_REG_1, 1),                /* r1 = 1 */
-        BPF_XADD(BPF_DW, BPF_REG_0, BPF_REG_1, 0, 0),
-                                /* lock *(u64 *) r0 += r1 */
-.\"                                == atomic64_add
-        BPF_MOV64_IMM(BPF_REG_0, 0),                /* r0 = 0 */
-        BPF_EXIT_INSN(),                            /* return r0 */
-    };
-
-    prog_fd = bpf_prog_load(BPF_PROG_TYPE_SOCKET_FILTER, prog,
-                            sizeof(prog) / sizeof(prog[0]), "GPL");
-
-    sock = open_raw_sock("lo");
-
-    assert(setsockopt(sock, SOL_SOCKET, SO_ATTACH_BPF, &prog_fd,
-                      sizeof(prog_fd)) == 0);
-
-    for (;;) {
-        key = IPPROTO_TCP;
-        assert(bpf_lookup_elem(map_fd, &key, &tcp_cnt) == 0);
-        key = IPPROTO_UDP;
-        assert(bpf_lookup_elem(map_fd, &key, &udp_cnt) == 0);
-        printf("TCP %lld UDP %lld packets\en", tcp_cnt, udp_cnt);
-        sleep(1);
-    }
-
-    return 0;
-}
-.EE
-.PP
-Some complete working code can be found in the
-.I samples/bpf
-directory in the kernel source tree.
 .SH RETURN VALUE
 For a successful call, the return value depends on the operation:
 .TP
@@ -1270,6 +1201,75 @@ MIPS 64 (since Linux 4.18; cBPF since Linux 3.16);
 riscv (since Linux 5.1).
 .\" commit 2353ecc6f91fd15b893fa01bf85a1c7a823ee4f2
 .PD
+.SH EXAMPLES
+.EX
+/* bpf+sockets example:
+ * 1. create array map of 256 elements
+ * 2. load program that counts number of packets received
+ *    r0 = skb->data[ETH_HLEN + offsetof(struct iphdr, protocol)]
+ *    map[r0]++
+ * 3. attach prog_fd to raw socket via setsockopt()
+ * 4. print number of received TCP/UDP packets every second
+ */
+int
+main(int argc, char **argv)
+{
+    int sock, map_fd, prog_fd, key;
+    long long value = 0, tcp_cnt, udp_cnt;
+
+    map_fd = bpf_create_map(BPF_MAP_TYPE_ARRAY, sizeof(key),
+                            sizeof(value), 256);
+    if (map_fd < 0) {
+        printf("failed to create map \(aq%s\(aq\en", strerror(errno));
+        /* likely not run as root */
+        return 1;
+    }
+
+    struct bpf_insn prog[] = {
+        BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),        /* r6 = r1 */
+        BPF_LD_ABS(BPF_B, ETH_HLEN + offsetof(struct iphdr, protocol)),
+                                /* r0 = ip->proto */
+        BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_0, -4),
+                                /* *(u32 *)(fp - 4) = r0 */
+        BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),       /* r2 = fp */
+        BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -4),      /* r2 = r2 - 4 */
+        BPF_LD_MAP_FD(BPF_REG_1, map_fd),           /* r1 = map_fd */
+        BPF_CALL_FUNC(BPF_FUNC_map_lookup_elem),
+                                /* r0 = map_lookup(r1, r2) */
+        BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 2),
+                                /* if (r0 == 0) goto pc+2 */
+        BPF_MOV64_IMM(BPF_REG_1, 1),                /* r1 = 1 */
+        BPF_XADD(BPF_DW, BPF_REG_0, BPF_REG_1, 0, 0),
+                                /* lock *(u64 *) r0 += r1 */
+.\"                                == atomic64_add
+        BPF_MOV64_IMM(BPF_REG_0, 0),                /* r0 = 0 */
+        BPF_EXIT_INSN(),                            /* return r0 */
+    };
+
+    prog_fd = bpf_prog_load(BPF_PROG_TYPE_SOCKET_FILTER, prog,
+                            sizeof(prog) / sizeof(prog[0]), "GPL");
+
+    sock = open_raw_sock("lo");
+
+    assert(setsockopt(sock, SOL_SOCKET, SO_ATTACH_BPF, &prog_fd,
+                      sizeof(prog_fd)) == 0);
+
+    for (;;) {
+        key = IPPROTO_TCP;
+        assert(bpf_lookup_elem(map_fd, &key, &tcp_cnt) == 0);
+        key = IPPROTO_UDP;
+        assert(bpf_lookup_elem(map_fd, &key, &udp_cnt) == 0);
+        printf("TCP %lld UDP %lld packets\en", tcp_cnt, udp_cnt);
+        sleep(1);
+    }
+
+    return 0;
+}
+.EE
+.PP
+Some complete working code can be found in the
+.I samples/bpf
+directory in the kernel source tree.
 .SH SEE ALSO
 .BR seccomp (2),
 .BR bpf\-helpers (7),