1 /*
2  * Copyright 2013 Google Inc.
3  * Author: Willem de Bruijn <willemb@google.com>
4  *         Daniel Borkmann <dborkman@redhat.com>
5  *
6  * License (GPLv2):
7  *
8  * This program is free software; you can redistribute it and/or modify it
9  * under the terms and conditions of the GNU General Public License,
10  * version 2, as published by the Free Software Foundation.
11  *
12  * This program is distributed in the hope it will be useful, but WITHOUT
13  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14  * FITNESS FOR A PARTICULAR PURPOSE. * See the GNU General Public License for
15  * more details.
16  *
17  * You should have received a copy of the GNU General Public License along with
18  * this program; if not, write to the Free Software Foundation, Inc.,
19  * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
20  */
21 
22 #ifndef PSOCK_LIB_H
23 #define PSOCK_LIB_H
24 
25 #include <sys/types.h>
26 #include <sys/socket.h>
27 #include <string.h>
28 #include <arpa/inet.h>
29 #include <unistd.h>
30 
31 #define DATA_LEN			100
32 #define DATA_CHAR			'a'
33 #define DATA_CHAR_1			'b'
34 
35 #define PORT_BASE			8000
36 
37 #ifndef __maybe_unused
38 # define __maybe_unused		__attribute__ ((__unused__))
39 #endif
40 
41 static __maybe_unused void pair_udp_setfilter(int fd)
42 {
43 	/* the filter below checks for all of the following conditions that
44 	 * are based on the contents of create_payload()
45 	 *  ether type 0x800 and
46 	 *  ip proto udp     and
47 	 *  skb->len == DATA_LEN and
48 	 *  udp[38] == 'a' or udp[38] == 'b'
49 	 * It can be generated from the following bpf_asm input:
50 	 *	ldh [12]
51 	 *	jne #0x800, drop	; ETH_P_IP
52 	 *	ldb [23]
53 	 *	jneq #17, drop		; IPPROTO_UDP
54 	 *	ld len			; ld skb->len
55 	 *	jlt #100, drop		; DATA_LEN
56 	 *	ldb [80]
57 	 *	jeq #97, pass		; DATA_CHAR
58 	 *	jne #98, drop		; DATA_CHAR_1
59 	 *	pass:
60 	 *	  ret #-1
61 	 *	drop:
62 	 *	  ret #0
63 	 */
64 	struct sock_filter bpf_filter[] = {
65 		{ 0x28,  0,  0, 0x0000000c },
66 		{ 0x15,  0,  8, 0x00000800 },
67 		{ 0x30,  0,  0, 0x00000017 },
68 		{ 0x15,  0,  6, 0x00000011 },
69 		{ 0x80,  0,  0, 0000000000 },
70 		{ 0x35,  0,  4, 0x00000064 },
71 		{ 0x30,  0,  0, 0x00000050 },
72 		{ 0x15,  1,  0, 0x00000061 },
73 		{ 0x15,  0,  1, 0x00000062 },
74 		{ 0x06,  0,  0, 0xffffffff },
75 		{ 0x06,  0,  0, 0000000000 },
76 	};
77 	struct sock_fprog bpf_prog;
78 
79 	bpf_prog.filter = bpf_filter;
80 	bpf_prog.len = sizeof(bpf_filter) / sizeof(struct sock_filter);
81 
82 	if (setsockopt(fd, SOL_SOCKET, SO_ATTACH_FILTER, &bpf_prog,
83 		       sizeof(bpf_prog))) {
84 		perror("setsockopt SO_ATTACH_FILTER");
85 		exit(1);
86 	}
87 }
88 
89 static __maybe_unused void pair_udp_open(int fds[], uint16_t port)
90 {
91 	struct sockaddr_in saddr, daddr;
92 
93 	fds[0] = socket(PF_INET, SOCK_DGRAM, 0);
94 	fds[1] = socket(PF_INET, SOCK_DGRAM, 0);
95 	if (fds[0] == -1 || fds[1] == -1) {
96 		fprintf(stderr, "ERROR: socket dgram\n");
97 		exit(1);
98 	}
99 
100 	memset(&saddr, 0, sizeof(saddr));
101 	saddr.sin_family = AF_INET;
102 	saddr.sin_port = htons(port);
103 	saddr.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
104 
105 	memset(&daddr, 0, sizeof(daddr));
106 	daddr.sin_family = AF_INET;
107 	daddr.sin_port = htons(port + 1);
108 	daddr.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
109 
110 	/* must bind both to get consistent hash result */
111 	if (bind(fds[1], (void *) &daddr, sizeof(daddr))) {
112 		perror("bind");
113 		exit(1);
114 	}
115 	if (bind(fds[0], (void *) &saddr, sizeof(saddr))) {
116 		perror("bind");
117 		exit(1);
118 	}
119 	if (connect(fds[0], (void *) &daddr, sizeof(daddr))) {
120 		perror("connect");
121 		exit(1);
122 	}
123 }
124 
125 static __maybe_unused void pair_udp_send_char(int fds[], int num, char payload)
126 {
127 	char buf[DATA_LEN], rbuf[DATA_LEN];
128 
129 	memset(buf, payload, sizeof(buf));
130 	while (num--) {
131 		/* Should really handle EINTR and EAGAIN */
132 		if (write(fds[0], buf, sizeof(buf)) != sizeof(buf)) {
133 			fprintf(stderr, "ERROR: send failed left=%d\n", num);
134 			exit(1);
135 		}
136 		if (read(fds[1], rbuf, sizeof(rbuf)) != sizeof(rbuf)) {
137 			fprintf(stderr, "ERROR: recv failed left=%d\n", num);
138 			exit(1);
139 		}
140 		if (memcmp(buf, rbuf, sizeof(buf))) {
141 			fprintf(stderr, "ERROR: data failed left=%d\n", num);
142 			exit(1);
143 		}
144 	}
145 }
146 
147 static __maybe_unused void pair_udp_send(int fds[], int num)
148 {
149 	return pair_udp_send_char(fds, num, DATA_CHAR);
150 }
151 
152 static __maybe_unused void pair_udp_close(int fds[])
153 {
154 	close(fds[0]);
155 	close(fds[1]);
156 }
157 
158 #endif /* PSOCK_LIB_H */
159