1/*
2 * em_cmp.c		Simle coparison 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 <dlfcn.h>
22#include <errno.h>
23
24#include "m_ematch.h"
25#include <linux/tc_ematch/tc_em_cmp.h>
26
27extern struct ematch_util cmp_ematch_util;
28
29static void cmp_print_usage(FILE *fd)
30{
31	fprintf(fd,
32	    "Usage: cmp(ALIGN at OFFSET [ ATTRS ] { eq | lt | gt } VALUE)\n" \
33	    "where: ALIGN  := { u8 | u16 | u32 }\n" \
34	    "       ATTRS  := [ layer LAYER ] [ mask MASK ] [ trans ]\n" \
35	    "       LAYER  := { link | header | next-header | 0..%d }\n" \
36	    "\n" \
37	    "Example: cmp(u16 at 3 layer 2 mask 0xff00 gt 20)\n",
38	    TCF_LAYER_MAX);
39}
40
41static int cmp_parse_eopt(struct nlmsghdr *n, struct tcf_ematch_hdr *hdr,
42			  struct bstr *args)
43{
44	struct bstr *a;
45	int align, opnd = 0;
46	unsigned long offset = 0, layer = TCF_LAYER_NETWORK, mask = 0, value = 0;
47	int offset_present = 0, value_present = 0;
48	struct tcf_em_cmp cmp;
49
50	memset(&cmp, 0, sizeof(cmp));
51
52#define PARSE_ERR(CARG, FMT, ARGS...) \
53	em_parse_error(EINVAL, args, CARG, &cmp_ematch_util, FMT ,##ARGS)
54
55	if (args == NULL)
56		return PARSE_ERR(args, "cmp: missing arguments");
57
58	if (!bstrcmp(args, "u8"))
59		align = TCF_EM_ALIGN_U8;
60	else if (!bstrcmp(args, "u16"))
61		align = TCF_EM_ALIGN_U16;
62	else if (!bstrcmp(args, "u32"))
63		align = TCF_EM_ALIGN_U32;
64	else
65		return PARSE_ERR(args, "cmp: invalid alignment");
66
67	for (a = bstr_next(args); a; a = bstr_next(a)) {
68		if (!bstrcmp(a, "at")) {
69			if (a->next == NULL)
70				return PARSE_ERR(a, "cmp: missing argument");
71			a = bstr_next(a);
72
73			offset = bstrtoul(a);
74			if (offset == ULONG_MAX)
75				return PARSE_ERR(a, "cmp: invalid offset, " \
76				    "must be numeric");
77
78			offset_present = 1;
79		} else if (!bstrcmp(a, "layer")) {
80			if (a->next == NULL)
81				return PARSE_ERR(a, "cmp: missing argument");
82			a = bstr_next(a);
83
84			layer = parse_layer(a);
85			if (layer == INT_MAX) {
86				layer = bstrtoul(a);
87				if (layer == ULONG_MAX)
88					return PARSE_ERR(a, "cmp: invalid " \
89					    "layer");
90			}
91
92			if (layer > TCF_LAYER_MAX)
93				return PARSE_ERR(a, "cmp: illegal layer, " \
94				    "must be in 0..%d", TCF_LAYER_MAX);
95		} else if (!bstrcmp(a, "mask")) {
96			if (a->next == NULL)
97				return PARSE_ERR(a, "cmp: missing argument");
98			a = bstr_next(a);
99
100			mask = bstrtoul(a);
101			if (mask == ULONG_MAX)
102				return PARSE_ERR(a, "cmp: invalid mask");
103		} else if (!bstrcmp(a, "trans")) {
104			cmp.flags |= TCF_EM_CMP_TRANS;
105		} else if (!bstrcmp(a, "eq") || !bstrcmp(a, "gt") ||
106		    !bstrcmp(a, "lt")) {
107
108			if (!bstrcmp(a, "eq"))
109				opnd = TCF_EM_OPND_EQ;
110			else if (!bstrcmp(a, "gt"))
111				opnd = TCF_EM_OPND_GT;
112			else if (!bstrcmp(a, "lt"))
113				opnd = TCF_EM_OPND_LT;
114
115			if (a->next == NULL)
116				return PARSE_ERR(a, "cmp: missing argument");
117			a = bstr_next(a);
118
119			value = bstrtoul(a);
120			if (value == ULONG_MAX)
121				return PARSE_ERR(a, "cmp: invalid value");
122
123			value_present = 1;
124		} else
125			return PARSE_ERR(a, "nbyte: unknown parameter");
126	}
127
128	if (offset_present == 0 || value_present == 0)
129		return PARSE_ERR(a, "cmp: offset and value required");
130
131	cmp.val = (__u32) value;
132	cmp.mask = (__u32) mask;
133	cmp.off = (__u16) offset;
134	cmp.align = (__u8) align;
135	cmp.layer = (__u8) layer;
136	cmp.opnd = (__u8) opnd;
137
138	addraw_l(n, MAX_MSG, hdr, sizeof(*hdr));
139	addraw_l(n, MAX_MSG, &cmp, sizeof(cmp));
140
141#undef PARSE_ERR
142	return 0;
143}
144
145static int cmp_print_eopt(FILE *fd, struct tcf_ematch_hdr *hdr, void *data,
146			  int data_len)
147{
148	struct tcf_em_cmp *cmp = data;
149
150	if (data_len < sizeof(*cmp)) {
151		fprintf(stderr, "CMP header size mismatch\n");
152		return -1;
153	}
154
155	if (cmp->align == TCF_EM_ALIGN_U8)
156		fprintf(fd, "u8 ");
157	else if (cmp->align == TCF_EM_ALIGN_U16)
158		fprintf(fd, "u16 ");
159	else if (cmp->align == TCF_EM_ALIGN_U16)
160		fprintf(fd, "u32 ");
161
162	fprintf(fd, "at %d layer %d ", cmp->off, cmp->layer);
163
164	if (cmp->mask)
165		fprintf(fd, "mask 0x%x ", cmp->mask);
166
167	if (cmp->flags & TCF_EM_CMP_TRANS)
168		fprintf(fd, "trans ");
169
170	if (cmp->opnd == TCF_EM_OPND_EQ)
171		fprintf(fd, "eq ");
172	else if (cmp->opnd == TCF_EM_OPND_LT)
173		fprintf(fd, "lt ");
174	else if (cmp->opnd == TCF_EM_OPND_GT)
175		fprintf(fd, "gt ");
176
177	fprintf(fd, "%d", cmp->val);
178
179	return 0;
180}
181
182struct ematch_util cmp_ematch_util = {
183	.kind = "cmp",
184	.kind_num = TCF_EM_CMP,
185	.parse_eopt = cmp_parse_eopt,
186	.print_eopt = cmp_print_eopt,
187	.print_usage = cmp_print_usage
188};
189