From a6a2d0c9fd97196a98cdf5f1389cd64eae7974b9 Mon Sep 17 00:00:00 2001 From: Fernando Fernandez Mancera Date: Wed, 19 Jun 2019 19:53:50 +0200 Subject: src: add synproxy support Signed-off-by: Fernando Fernandez Mancera Signed-off-by: Pablo Neira Ayuso --- include/libnftnl/expr.h | 6 ++ include/linux/netfilter/nf_tables.h | 17 ++++ src/Makefile.am | 1 + src/expr/synproxy.c | 170 ++++++++++++++++++++++++++++++++++++ src/expr_ops.c | 2 + 5 files changed, 196 insertions(+) create mode 100644 src/expr/synproxy.c diff --git a/include/libnftnl/expr.h b/include/libnftnl/expr.h index b2f8d75..3e0f5b0 100644 --- a/include/libnftnl/expr.h +++ b/include/libnftnl/expr.h @@ -291,6 +291,12 @@ enum { NFTNL_EXPR_XFRM_SPNUM, }; +enum { + NFTNL_EXPR_SYNPROXY_MSS = NFTNL_EXPR_BASE, + NFTNL_EXPR_SYNPROXY_WSCALE, + NFTNL_EXPR_SYNPROXY_FLAGS, +}; + #ifdef __cplusplus } /* extern "C" */ #endif diff --git a/include/linux/netfilter/nf_tables.h b/include/linux/netfilter/nf_tables.h index 5b1c380..4777331 100644 --- a/include/linux/netfilter/nf_tables.h +++ b/include/linux/netfilter/nf_tables.h @@ -953,6 +953,23 @@ enum nft_osf_attributes { }; #define NFTA_OSF_MAX (__NFTA_OSF_MAX - 1) +/** + * enum nft_synproxy_attributes - nf_tables synproxy expression + * netlink attributes + * + * @NFTA_SYNPROXY_MSS: mss value sent to the backend (NLA_U16) + * @NFTA_SYNPROXY_WSCALE: wscale value sent to the backend (NLA_U8) + * @NFTA_SYNPROXY_FLAGS: flags (NLA_U32) + */ +enum nft_synproxy_attributes { + NFTA_SYNPROXY_UNSPEC, + NFTA_SYNPROXY_MSS, + NFTA_SYNPROXY_WSCALE, + NFTA_SYNPROXY_FLAGS, + __NFTA_SYNPROXY_MAX, +}; +#define NFTA_SYNPROXY_MAX (__NFTA_SYNPROXY_MAX - 1) + /** * enum nft_ct_keys - nf_tables ct expression keys * diff --git a/src/Makefile.am b/src/Makefile.am index 8f9c022..f16422c 100644 --- a/src/Makefile.am +++ b/src/Makefile.am @@ -56,6 +56,7 @@ libnftnl_la_SOURCES = utils.c \ expr/redir.c \ expr/hash.c \ expr/socket.c \ + expr/synproxy.c \ expr/osf.c \ expr/xfrm.c \ obj/counter.c \ diff --git a/src/expr/synproxy.c b/src/expr/synproxy.c new file mode 100644 index 0000000..245f4fb --- /dev/null +++ b/src/expr/synproxy.c @@ -0,0 +1,170 @@ +#include +#include +#include +#include +#include +#include + +#include "internal.h" +#include +#include +#include + +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_default(char *buf, size_t size, + const struct nftnl_expr *e) +{ + struct nftnl_expr_synproxy *synproxy = nftnl_expr_data(e); + int ret, offset = 0, len = size; + + 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; +} + +static int +nftnl_expr_synproxy_snprintf(char *buf, size_t len, uint32_t type, + uint32_t flags, const struct nftnl_expr *e) +{ + switch(type) { + case NFTNL_OUTPUT_DEFAULT: + return nftnl_expr_synproxy_snprintf_default(buf, len, e); + case NFTNL_OUTPUT_XML: + case NFTNL_OUTPUT_JSON: + default: + break; + } + return -1; +} + +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, + .snprintf = nftnl_expr_synproxy_snprintf, +}; diff --git a/src/expr_ops.c b/src/expr_ops.c index 051140f..3538dd6 100644 --- a/src/expr_ops.c +++ b/src/expr_ops.c @@ -37,6 +37,7 @@ extern struct expr_ops expr_ops_hash; extern struct expr_ops expr_ops_fib; extern struct expr_ops expr_ops_flow; extern struct expr_ops expr_ops_socket; +extern struct expr_ops expr_ops_synproxy; extern struct expr_ops expr_ops_tunnel; extern struct expr_ops expr_ops_osf; extern struct expr_ops expr_ops_xfrm; @@ -80,6 +81,7 @@ static struct expr_ops *expr_ops[] = { &expr_ops_objref, &expr_ops_flow, &expr_ops_socket, + &expr_ops_synproxy, &expr_ops_tunnel, &expr_ops_osf, &expr_ops_xfrm, -- cgit v1.2.3