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      1 /*
      2  * Copyright 2013 Google Inc.
      3  * Author: Willem de Bruijn <willemb (at) google.com>
      4  *         Daniel Borkmann <dborkman (at) 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