diff options
Diffstat (limited to '')
| -rw-r--r-- | src/expr/synproxy.c | 156 |
1 files changed, 156 insertions, 0 deletions
diff --git a/src/expr/synproxy.c b/src/expr/synproxy.c new file mode 100644 index 0000000..47fcaef --- /dev/null +++ b/src/expr/synproxy.c @@ -0,0 +1,156 @@ +#include <stdio.h> +#include <stdint.h> +#include <string.h> +#include <arpa/inet.h> +#include <errno.h> +#include <linux/netfilter/nf_tables.h> + +#include "internal.h" +#include <libmnl/libmnl.h> +#include <libnftnl/expr.h> +#include <libnftnl/rule.h> + +struct nftnl_expr_synproxy { + uint16_t mss; + uint8_t wscale; + uint32_t flags; +}; + +static int nftnl_expr_synproxy_set(struct nftnl_expr *e, uint16_t type, + const void *data, uint32_t data_len) +{ + struct nftnl_expr_synproxy *synproxy = nftnl_expr_data(e); + + switch(type) { + case NFTNL_EXPR_SYNPROXY_MSS: + memcpy(&synproxy->mss, data, sizeof(synproxy->mss)); + break; + case NFTNL_EXPR_SYNPROXY_WSCALE: + memcpy(&synproxy->wscale, data, sizeof(synproxy->wscale)); + break; + case NFTNL_EXPR_SYNPROXY_FLAGS: + memcpy(&synproxy->flags, data, sizeof(synproxy->flags)); + break; + } + return 0; +} + +static const void * +nftnl_expr_synproxy_get(const struct nftnl_expr *e, uint16_t type, + uint32_t *data_len) +{ + struct nftnl_expr_synproxy *synproxy = nftnl_expr_data(e); + + switch(type) { + case NFTNL_EXPR_SYNPROXY_MSS: + *data_len = sizeof(synproxy->mss); + return &synproxy->mss; + case NFTNL_EXPR_SYNPROXY_WSCALE: + *data_len = sizeof(synproxy->wscale); + return &synproxy->wscale; + case NFTNL_EXPR_SYNPROXY_FLAGS: + *data_len = sizeof(synproxy->flags); + return &synproxy->flags; + } + return NULL; +} + +static int nftnl_expr_synproxy_cb(const struct nlattr *attr, void *data) +{ + const struct nlattr **tb = data; + int type = mnl_attr_get_type(attr); + + if (mnl_attr_type_valid(attr, NFTA_SYNPROXY_MAX) < 0) + return MNL_CB_OK; + + switch(type) { + case NFTNL_EXPR_SYNPROXY_MSS: + if (mnl_attr_validate(attr, MNL_TYPE_U16) < 0) + abi_breakage(); + break; + + case NFTNL_EXPR_SYNPROXY_WSCALE: + if (mnl_attr_validate(attr, MNL_TYPE_U8) < 0) + abi_breakage(); + break; + + case NFTNL_EXPR_SYNPROXY_FLAGS: + if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0) + abi_breakage(); + break; + } + + tb[type] = attr; + return MNL_CB_OK; +} + +static void +nftnl_expr_synproxy_build(struct nlmsghdr *nlh, const struct nftnl_expr *e) +{ + struct nftnl_expr_synproxy *synproxy = nftnl_expr_data(e); + + if (e->flags & (1 << NFTNL_EXPR_SYNPROXY_MSS)) + mnl_attr_put_u16(nlh, NFTNL_EXPR_SYNPROXY_MSS, + htons(synproxy->mss)); + if (e->flags & (1 << NFTNL_EXPR_SYNPROXY_WSCALE)) + mnl_attr_put_u8(nlh, NFTNL_EXPR_SYNPROXY_WSCALE, + synproxy->wscale); + if (e->flags & (1 << NFTNL_EXPR_SYNPROXY_FLAGS)) + mnl_attr_put_u32(nlh, NFTNL_EXPR_SYNPROXY_FLAGS, + htonl(synproxy->flags)); +} + +static int +nftnl_expr_synproxy_parse(struct nftnl_expr *e, struct nlattr *attr) +{ + struct nftnl_expr_synproxy *synproxy = nftnl_expr_data(e); + struct nlattr *tb[NFTA_SYNPROXY_MAX + 1] = {}; + + if (mnl_attr_parse_nested(attr, nftnl_expr_synproxy_cb, tb) < 0) + return -1; + + if (tb[NFTA_SYNPROXY_MSS]) { + synproxy->mss = ntohs(mnl_attr_get_u16(tb[NFTA_SYNPROXY_MSS])); + e->flags |= (1 << NFTNL_EXPR_SYNPROXY_MSS); + } + + if (tb[NFTA_SYNPROXY_WSCALE]) { + synproxy->wscale = mnl_attr_get_u8(tb[NFTA_SYNPROXY_WSCALE]); + e->flags |= (1 << NFTNL_EXPR_SYNPROXY_WSCALE); + } + + if (tb[NFTA_SYNPROXY_FLAGS]) { + synproxy->flags = ntohl(mnl_attr_get_u32(tb[NFTA_SYNPROXY_FLAGS])); + e->flags |= (1 << NFTNL_EXPR_SYNPROXY_FLAGS); + } + + return 0; +} + +static int +nftnl_expr_synproxy_snprintf(char *buf, size_t len, + uint32_t flags, const struct nftnl_expr *e) +{ + struct nftnl_expr_synproxy *synproxy = nftnl_expr_data(e); + int ret, offset = 0; + + if (e->flags & (1 << NFTNL_EXPR_SYNPROXY_MSS) && + e->flags & (1 << NFTNL_EXPR_SYNPROXY_WSCALE)) { + ret = snprintf(buf, len, "mss %u wscale %u ", synproxy->mss, + synproxy->wscale); + SNPRINTF_BUFFER_SIZE(ret, len, offset); + } + + return offset; +} + +struct expr_ops expr_ops_synproxy = { + .name = "synproxy", + .alloc_len = sizeof(struct nftnl_expr_synproxy), + .max_attr = NFTA_SYNPROXY_MAX, + .set = nftnl_expr_synproxy_set, + .get = nftnl_expr_synproxy_get, + .parse = nftnl_expr_synproxy_parse, + .build = nftnl_expr_synproxy_build, + .output = nftnl_expr_synproxy_snprintf, +}; |