1 /*
2  * Copyright (c) 2014 The DragonFly Project.  All rights reserved.
3  *
4  * This code is derived from software contributed to The DragonFly Project
5  * by Bill Yuan <bycn82@gmail.com>
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  *
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in
15  *    the documentation and/or other materials provided with the
16  *    distribution.
17  * 3. Neither the name of The DragonFly Project nor the names of its
18  *    contributors may be used to endorse or promote products derived
19  *    from this software without specific, prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
23  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
24  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
25  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
26  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
27  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
28  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
29  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
30  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
31  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  */
34 
35 #include <err.h>
36 #include <errno.h>
37 #include <grp.h>
38 #include <pwd.h>
39 #include <pcap.h>
40 #include <stdio.h>
41 #include <stdlib.h>
42 #include <string.h>
43 #include <sysexits.h>
44 
45 #include <net/if.h>
46 #include <net/route.h>
47 #include <net/pfil.h>
48 #include <netinet/in.h>
49 
50 #include "../../../sys/net/ipfw3/ip_fw3.h"
51 #include "../../../sbin/ipfw3/ipfw.h"
52 #include "ipfw3_layer4.h"
53 
54 int
55 char_at(char *str, char c)
56 {
57 	int pos;
58 	for (pos = 0; str[pos] != '\0'; pos++) {
59 		if (str[pos] == c)
60 			return pos;
61 	}
62 	return -1;
63 }
64 
65 void
66 parse_tcpflag(ipfw_insn **cmd, int *ac, char **av[])
67 {
68 	(*cmd)->opcode = O_LAYER4_TCPFLAG;
69 	(*cmd)->module = MODULE_LAYER4_ID;
70 	(*cmd)->len =  ((*cmd)->len&(F_NOT|F_OR))|LEN_OF_IPFWINSN;
71 	/* XXX TODO parse the tcpflag value and store in arg1 or arg3 */
72 	NEXT_ARG1;
73 }
74 
75 void
76 parse_uid(ipfw_insn **cmd, int *ac, char **av[])
77 {
78 	char *end;
79 	uid_t uid;
80 	struct passwd *pwd;
81 
82 	NEXT_ARG1;
83 	ipfw_insn_u32 *cmd32 = (ipfw_insn_u32 *)(*cmd);
84 	uid = strtoul(**av, &end, 0);
85 	pwd = (*end == '\0') ? getpwuid(uid) : getpwnam(**av);
86 	if (pwd == NULL)
87 		errx(EX_DATAERR, "uid \"%s\" not exists", **av);
88 
89 	cmd32->d[0] = pwd->pw_uid;
90 
91 	(*cmd)->opcode = O_LAYER4_UID;
92 	(*cmd)->module = MODULE_LAYER4_ID;
93 	(*cmd)->len = F_INSN_SIZE(ipfw_insn_u32);
94 	NEXT_ARG1;
95 }
96 
97 void
98 parse_gid(ipfw_insn **cmd, int *ac, char **av[])
99 {
100 	char *end;
101 	gid_t gid;
102 	struct group *grp;
103 
104 	NEXT_ARG1;
105 	ipfw_insn_u32 *cmd32 = (ipfw_insn_u32 *)(*cmd);
106 	gid = strtoul(**av, &end, 0);
107 	grp = (*end == '\0') ? getgrgid(gid) : getgrnam(**av);
108 	if (grp == NULL)
109 		errx(EX_DATAERR, "gid \"%s\" not exists", **av);
110 
111 	cmd32->d[0] = grp->gr_gid;
112 
113 	(*cmd)->opcode = O_LAYER4_GID;
114 	(*cmd)->module = MODULE_LAYER4_ID;
115 	(*cmd)->len = F_INSN_SIZE(ipfw_insn_u32);
116 	NEXT_ARG1;
117 }
118 
119 void
120 parse_established(ipfw_insn **cmd, int *ac, char **av[])
121 {
122 	NEXT_ARG1;
123 	(*cmd)->opcode = O_LAYER4_ESTABLISHED;
124 	(*cmd)->module = MODULE_LAYER4_ID;
125 	(*cmd)->len |= LEN_OF_IPFWINSN;
126 }
127 
128 void
129 parse_bpf(ipfw_insn **cmd, int *ac, char **av[])
130 {
131 	struct bpf_program program;
132 	ipfw_insn_bpf *bpf;
133 	int avlen;
134 
135 	NEXT_ARG1;
136 	(*cmd)->opcode = O_LAYER4_BPF;
137 	(*cmd)->module = MODULE_LAYER4_ID;
138 
139 	avlen = strlen(**av);
140 	if (avlen > 256)
141 		errx(EX_DATAERR, "bpf \"%s\" too long (max 256)", **av);
142 	bpf = (ipfw_insn_bpf *)(*cmd);
143 	strcpy(bpf->bf_str, **av);
144 	if (pcap_compile_nopcap(65535, DLT_RAW, &program, **av, 1,
145 			PCAP_NETMASK_UNKNOWN))
146 		errx(EX_DATAERR, "bpf \"%s\" compilation error", **av);
147 	bpf->bf_len = program.bf_len;
148 
149 	memcpy(&bpf->bf_insn, program.bf_insns,
150 			sizeof(struct bpf_insn) * program.bf_len);
151 	(*cmd)->len |= (sizeof(ipfw_insn_bpf) +
152 			sizeof(struct bpf_insn) * (bpf->bf_len - 1)) /
153 			sizeof(uint32_t);
154 
155 	pcap_freecode(&program);
156 	NEXT_ARG1;
157 }
158 
159 void
160 show_tcpflag(ipfw_insn *cmd, int show_or)
161 {
162 	printf(" tcpflag %d", cmd->arg1);
163 }
164 
165 void
166 show_uid(ipfw_insn *cmd, int show_or)
167 {
168 	ipfw_insn_u32 *cmd32 = (ipfw_insn_u32 *)cmd;
169 	struct passwd *pwd = getpwuid(cmd32->d[0]);
170 	if (pwd){
171 		printf(" uid %s", pwd->pw_name);
172 	}else{
173 		printf(" uid %u", cmd32->d[0]);
174 	}
175 }
176 
177 void
178 show_gid(ipfw_insn *cmd, int show_or)
179 {
180 	ipfw_insn_u32 *cmd32 = (ipfw_insn_u32 *)cmd;
181 	struct group *grp = getgrgid(cmd32->d[0]);
182 	if (grp){
183 		printf(" gid %s", grp->gr_name);
184 	}else{
185 		printf(" gid %u", cmd32->d[0]);
186 	}
187 }
188 
189 void
190 show_established(ipfw_insn *cmd, int show_or)
191 {
192 	printf(" established");
193 }
194 
195 void
196 show_bpf(ipfw_insn *cmd, int show_or)
197 {
198 	ipfw_insn_bpf *bpf;
199 	char *word = "bpf";
200 	if (show_or)
201 		word = "or";
202 	bpf = (ipfw_insn_bpf *)cmd;
203 	printf(" %s \"%s\"", word, bpf->bf_str);
204 }
205 
206 void
207 load_module(register_func function, register_keyword keyword)
208 {
209 	keyword(MODULE_LAYER4_ID, O_LAYER4_TCPFLAG, "tcpflag", FILTER);
210 	function(MODULE_LAYER4_ID, O_LAYER4_TCPFLAG,
211 			(parser_func)parse_tcpflag, (shower_func)show_tcpflag);
212 	keyword(MODULE_LAYER4_ID, O_LAYER4_UID, "uid", FILTER);
213 	function(MODULE_LAYER4_ID, O_LAYER4_UID,
214 			(parser_func)parse_uid, (shower_func)show_uid);
215 	keyword(MODULE_LAYER4_ID, O_LAYER4_GID, "gid", FILTER);
216 	function(MODULE_LAYER4_ID, O_LAYER4_GID,
217 			(parser_func)parse_gid, (shower_func)show_gid);
218 	keyword(MODULE_LAYER4_ID, O_LAYER4_ESTABLISHED, "established", FILTER);
219 	function(MODULE_LAYER4_ID, O_LAYER4_ESTABLISHED,
220 			(parser_func)parse_established, (shower_func)show_established);
221 	keyword(MODULE_LAYER4_ID, O_LAYER4_BPF, "bpf", FILTER);
222 	function(MODULE_LAYER4_ID, O_LAYER4_BPF,
223 			(parser_func)parse_bpf, (shower_func)show_bpf);
224 }
225