1 /*
2 * em_cmp.c Simple comparison Ematch
3 *
4 * This program is free software; you can distribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation; either version
7 * 2 of the License, or (at your option) any later version.
8 *
9 * Authors: Thomas Graf <tgraf@suug.ch>
10 */
11
12 #include <stdio.h>
13 #include <stdlib.h>
14 #include <unistd.h>
15 #include <syslog.h>
16 #include <fcntl.h>
17 #include <sys/socket.h>
18 #include <netinet/in.h>
19 #include <arpa/inet.h>
20 #include <string.h>
21 #include <errno.h>
22
23 #include "m_ematch.h"
24 #include <linux/tc_ematch/tc_em_cmp.h>
25
26 extern struct ematch_util cmp_ematch_util;
27
cmp_print_usage(FILE * fd)28 static void cmp_print_usage(FILE *fd)
29 {
30 fprintf(fd,
31 "Usage: cmp(ALIGN at OFFSET [ ATTRS ] { eq | lt | gt } VALUE)\n" \
32 "where: ALIGN := { u8 | u16 | u32 }\n" \
33 " ATTRS := [ layer LAYER ] [ mask MASK ] [ trans ]\n" \
34 " LAYER := { link | network | transport | 0..%d }\n" \
35 "\n" \
36 "Example: cmp(u16 at 3 layer 2 mask 0xff00 gt 20)\n",
37 TCF_LAYER_MAX);
38 }
39
cmp_parse_eopt(struct nlmsghdr * n,struct tcf_ematch_hdr * hdr,struct bstr * args)40 static int cmp_parse_eopt(struct nlmsghdr *n, struct tcf_ematch_hdr *hdr,
41 struct bstr *args)
42 {
43 struct bstr *a;
44 int align, opnd = 0;
45 unsigned long offset = 0, layer = TCF_LAYER_NETWORK, mask = 0, value = 0;
46 int offset_present = 0, value_present = 0;
47 struct tcf_em_cmp cmp;
48
49 memset(&cmp, 0, sizeof(cmp));
50
51 #define PARSE_ERR(CARG, FMT, ARGS...) \
52 em_parse_error(EINVAL, args, CARG, &cmp_ematch_util, FMT ,##ARGS)
53
54 if (args == NULL)
55 return PARSE_ERR(args, "cmp: missing arguments");
56
57 if (!bstrcmp(args, "u8"))
58 align = TCF_EM_ALIGN_U8;
59 else if (!bstrcmp(args, "u16"))
60 align = TCF_EM_ALIGN_U16;
61 else if (!bstrcmp(args, "u32"))
62 align = TCF_EM_ALIGN_U32;
63 else
64 return PARSE_ERR(args, "cmp: invalid alignment");
65
66 for (a = bstr_next(args); a; a = bstr_next(a)) {
67 if (!bstrcmp(a, "at")) {
68 if (a->next == NULL)
69 return PARSE_ERR(a, "cmp: missing argument");
70 a = bstr_next(a);
71
72 offset = bstrtoul(a);
73 if (offset == ULONG_MAX)
74 return PARSE_ERR(a, "cmp: invalid offset, " \
75 "must be numeric");
76
77 offset_present = 1;
78 } else if (!bstrcmp(a, "layer")) {
79 if (a->next == NULL)
80 return PARSE_ERR(a, "cmp: missing argument");
81 a = bstr_next(a);
82
83 layer = parse_layer(a);
84 if (layer == INT_MAX) {
85 layer = bstrtoul(a);
86 if (layer == ULONG_MAX)
87 return PARSE_ERR(a, "cmp: invalid " \
88 "layer");
89 }
90
91 if (layer > TCF_LAYER_MAX)
92 return PARSE_ERR(a, "cmp: illegal layer, " \
93 "must be in 0..%d", TCF_LAYER_MAX);
94 } else if (!bstrcmp(a, "mask")) {
95 if (a->next == NULL)
96 return PARSE_ERR(a, "cmp: missing argument");
97 a = bstr_next(a);
98
99 mask = bstrtoul(a);
100 if (mask == ULONG_MAX)
101 return PARSE_ERR(a, "cmp: invalid mask");
102 } else if (!bstrcmp(a, "trans")) {
103 cmp.flags |= TCF_EM_CMP_TRANS;
104 } else if (!bstrcmp(a, "eq") || !bstrcmp(a, "gt") ||
105 !bstrcmp(a, "lt")) {
106
107 if (!bstrcmp(a, "eq"))
108 opnd = TCF_EM_OPND_EQ;
109 else if (!bstrcmp(a, "gt"))
110 opnd = TCF_EM_OPND_GT;
111 else if (!bstrcmp(a, "lt"))
112 opnd = TCF_EM_OPND_LT;
113
114 if (a->next == NULL)
115 return PARSE_ERR(a, "cmp: missing argument");
116 a = bstr_next(a);
117
118 value = bstrtoul(a);
119 if (value == ULONG_MAX)
120 return PARSE_ERR(a, "cmp: invalid value");
121
122 value_present = 1;
123 } else
124 return PARSE_ERR(a, "nbyte: unknown parameter");
125 }
126
127 if (offset_present == 0 || value_present == 0)
128 return PARSE_ERR(a, "cmp: offset and value required");
129
130 cmp.val = (__u32) value;
131 cmp.mask = (__u32) mask;
132 cmp.off = (__u16) offset;
133 cmp.align = (__u8) align;
134 cmp.layer = (__u8) layer;
135 cmp.opnd = (__u8) opnd;
136
137 addraw_l(n, MAX_MSG, hdr, sizeof(*hdr));
138 addraw_l(n, MAX_MSG, &cmp, sizeof(cmp));
139
140 #undef PARSE_ERR
141 return 0;
142 }
143
cmp_print_eopt(FILE * fd,struct tcf_ematch_hdr * hdr,void * data,int data_len)144 static int cmp_print_eopt(FILE *fd, struct tcf_ematch_hdr *hdr, void *data,
145 int data_len)
146 {
147 struct tcf_em_cmp *cmp = data;
148
149 if (data_len < sizeof(*cmp)) {
150 fprintf(stderr, "CMP header size mismatch\n");
151 return -1;
152 }
153
154 if (cmp->align == TCF_EM_ALIGN_U8)
155 fprintf(fd, "u8 ");
156 else if (cmp->align == TCF_EM_ALIGN_U16)
157 fprintf(fd, "u16 ");
158 else if (cmp->align == TCF_EM_ALIGN_U32)
159 fprintf(fd, "u32 ");
160
161 fprintf(fd, "at %d layer %d ", cmp->off, cmp->layer);
162
163 if (cmp->mask)
164 fprintf(fd, "mask 0x%x ", cmp->mask);
165
166 if (cmp->flags & TCF_EM_CMP_TRANS)
167 fprintf(fd, "trans ");
168
169 if (cmp->opnd == TCF_EM_OPND_EQ)
170 fprintf(fd, "eq ");
171 else if (cmp->opnd == TCF_EM_OPND_LT)
172 fprintf(fd, "lt ");
173 else if (cmp->opnd == TCF_EM_OPND_GT)
174 fprintf(fd, "gt ");
175
176 fprintf(fd, "%d", cmp->val);
177
178 return 0;
179 }
180
181 struct ematch_util cmp_ematch_util = {
182 .kind = "cmp",
183 .kind_num = TCF_EM_CMP,
184 .parse_eopt = cmp_parse_eopt,
185 .print_eopt = cmp_print_eopt,
186 .print_usage = cmp_print_usage
187 };
188