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Diffstat (limited to '')
| -rw-r--r-- | tc/em_cmp.c | 184 |
1 files changed, 184 insertions, 0 deletions
diff --git a/tc/em_cmp.c b/tc/em_cmp.c new file mode 100644 index 0000000..e051656 --- /dev/null +++ b/tc/em_cmp.c @@ -0,0 +1,184 @@ +/* + * em_cmp.c Simple comparison Ematch + * + * This program is free software; you can distribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + * + * Authors: Thomas Graf <tgraf@suug.ch> + */ + +#include <stdio.h> +#include <stdlib.h> +#include <unistd.h> +#include <fcntl.h> +#include <sys/socket.h> +#include <netinet/in.h> +#include <arpa/inet.h> +#include <string.h> +#include <errno.h> + +#include "m_ematch.h" +#include <linux/tc_ematch/tc_em_cmp.h> + +extern struct ematch_util cmp_ematch_util; + +static void cmp_print_usage(FILE *fd) +{ + fprintf(fd, + "Usage: cmp(ALIGN at OFFSET [ ATTRS ] { eq | lt | gt } VALUE)\n" \ + "where: ALIGN := { u8 | u16 | u32 }\n" \ + " ATTRS := [ layer LAYER ] [ mask MASK ] [ trans ]\n" \ + " LAYER := { link | network | transport | 0..%d }\n" \ + "\n" \ + "Example: cmp(u16 at 3 layer 2 mask 0xff00 gt 20)\n", + TCF_LAYER_MAX); +} + +static int cmp_parse_eopt(struct nlmsghdr *n, struct tcf_ematch_hdr *hdr, + struct bstr *args) +{ + struct bstr *a; + int align, opnd = 0; + unsigned long offset = 0, layer = TCF_LAYER_NETWORK, mask = 0, value = 0; + int offset_present = 0, value_present = 0; + struct tcf_em_cmp cmp = {}; + +#define PARSE_ERR(CARG, FMT, ARGS...) \ + em_parse_error(EINVAL, args, CARG, &cmp_ematch_util, FMT, ##ARGS) + + if (args == NULL) + return PARSE_ERR(args, "cmp: missing arguments"); + + if (!bstrcmp(args, "u8")) + align = TCF_EM_ALIGN_U8; + else if (!bstrcmp(args, "u16")) + align = TCF_EM_ALIGN_U16; + else if (!bstrcmp(args, "u32")) + align = TCF_EM_ALIGN_U32; + else + return PARSE_ERR(args, "cmp: invalid alignment"); + + for (a = bstr_next(args); a; a = bstr_next(a)) { + if (!bstrcmp(a, "at")) { + if (a->next == NULL) + return PARSE_ERR(a, "cmp: missing argument"); + a = bstr_next(a); + + offset = bstrtoul(a); + if (offset == ULONG_MAX) + return PARSE_ERR(a, "cmp: invalid offset, " \ + "must be numeric"); + + offset_present = 1; + } else if (!bstrcmp(a, "layer")) { + if (a->next == NULL) + return PARSE_ERR(a, "cmp: missing argument"); + a = bstr_next(a); + + layer = parse_layer(a); + if (layer == INT_MAX) { + layer = bstrtoul(a); + if (layer == ULONG_MAX) + return PARSE_ERR(a, "cmp: invalid " \ + "layer"); + } + + if (layer > TCF_LAYER_MAX) + return PARSE_ERR(a, "cmp: illegal layer, " \ + "must be in 0..%d", TCF_LAYER_MAX); + } else if (!bstrcmp(a, "mask")) { + if (a->next == NULL) + return PARSE_ERR(a, "cmp: missing argument"); + a = bstr_next(a); + + mask = bstrtoul(a); + if (mask == ULONG_MAX) + return PARSE_ERR(a, "cmp: invalid mask"); + } else if (!bstrcmp(a, "trans")) { + cmp.flags |= TCF_EM_CMP_TRANS; + } else if (!bstrcmp(a, "eq") || !bstrcmp(a, "gt") || + !bstrcmp(a, "lt")) { + + if (!bstrcmp(a, "eq")) + opnd = TCF_EM_OPND_EQ; + else if (!bstrcmp(a, "gt")) + opnd = TCF_EM_OPND_GT; + else if (!bstrcmp(a, "lt")) + opnd = TCF_EM_OPND_LT; + + if (a->next == NULL) + return PARSE_ERR(a, "cmp: missing argument"); + a = bstr_next(a); + + value = bstrtoul(a); + if (value == ULONG_MAX) + return PARSE_ERR(a, "cmp: invalid value"); + + value_present = 1; + } else + return PARSE_ERR(a, "nbyte: unknown parameter"); + } + + if (offset_present == 0 || value_present == 0) + return PARSE_ERR(a, "cmp: offset and value required"); + + cmp.val = (__u32) value; + cmp.mask = (__u32) mask; + cmp.off = (__u16) offset; + cmp.align = (__u8) align; + cmp.layer = (__u8) layer; + cmp.opnd = (__u8) opnd; + + addraw_l(n, MAX_MSG, hdr, sizeof(*hdr)); + addraw_l(n, MAX_MSG, &cmp, sizeof(cmp)); + +#undef PARSE_ERR + return 0; +} + +static int cmp_print_eopt(FILE *fd, struct tcf_ematch_hdr *hdr, void *data, + int data_len) +{ + struct tcf_em_cmp *cmp = data; + + if (data_len < sizeof(*cmp)) { + fprintf(stderr, "CMP header size mismatch\n"); + return -1; + } + + if (cmp->align == TCF_EM_ALIGN_U8) + fprintf(fd, "u8 "); + else if (cmp->align == TCF_EM_ALIGN_U16) + fprintf(fd, "u16 "); + else if (cmp->align == TCF_EM_ALIGN_U32) + fprintf(fd, "u32 "); + + fprintf(fd, "at %d layer %d ", cmp->off, cmp->layer); + + if (cmp->mask) + fprintf(fd, "mask 0x%x ", cmp->mask); + + if (cmp->flags & TCF_EM_CMP_TRANS) + fprintf(fd, "trans "); + + if (cmp->opnd == TCF_EM_OPND_EQ) + fprintf(fd, "eq "); + else if (cmp->opnd == TCF_EM_OPND_LT) + fprintf(fd, "lt "); + else if (cmp->opnd == TCF_EM_OPND_GT) + fprintf(fd, "gt "); + + fprintf(fd, "%d", cmp->val); + + return 0; +} + +struct ematch_util cmp_ematch_util = { + .kind = "cmp", + .kind_num = TCF_EM_CMP, + .parse_eopt = cmp_parse_eopt, + .print_eopt = cmp_print_eopt, + .print_usage = cmp_print_usage +}; |