#include #include #include #include struct nft_osf { enum nft_registers dreg:8; }; static const struct nla_policy nft_osf_policy[NFTA_OSF_MAX + 1] = { [NFTA_OSF_DREG] = { .type = NLA_U32 }, }; static void nft_osf_eval(const struct nft_expr *expr, struct nft_regs *regs, const struct nft_pktinfo *pkt) { struct nft_osf *priv = nft_expr_priv(expr); u32 *dest = ®s->data[priv->dreg]; struct sk_buff *skb = pkt->skb; const struct tcphdr *tcp; struct tcphdr _tcph; const char *os_name; if (pkt->tprot != IPPROTO_TCP) { regs->verdict.code = NFT_BREAK; return; } tcp = skb_header_pointer(skb, ip_hdrlen(skb), sizeof(struct tcphdr), &_tcph); if (!tcp) { regs->verdict.code = NFT_BREAK; return; } if (!tcp->syn) { regs->verdict.code = NFT_BREAK; return; } os_name = nf_osf_find(skb, nf_osf_fingers); if (!os_name) strncpy((char *)dest, "unknown", NFT_OSF_MAXGENRELEN); else strncpy((char *)dest, os_name, NFT_OSF_MAXGENRELEN); } static int nft_osf_init(const struct nft_ctx *ctx, const struct nft_expr *expr, const struct nlattr * const tb[]) { struct nft_osf *priv = nft_expr_priv(expr); int err; if (!tb[NFTA_OSF_DREG]) return -EINVAL; priv->dreg = nft_parse_register(tb[NFTA_OSF_DREG]); err = nft_validate_register_store(ctx, priv->dreg, NULL, NFT_DATA_VALUE, NFT_OSF_MAXGENRELEN); if (err < 0) return err; return 0; } static int nft_osf_dump(struct sk_buff *skb, const struct nft_expr *expr) { const struct nft_osf *priv = nft_expr_priv(expr); if (nft_dump_register(skb, NFTA_OSF_DREG, priv->dreg)) goto nla_put_failure; return 0; nla_put_failure: return -1; } static int nft_osf_validate(const struct nft_ctx *ctx, const struct nft_expr *expr, const struct nft_data **data) { return nft_chain_validate_hooks(ctx->chain, (1 << NF_INET_LOCAL_IN) | (1 << NF_INET_PRE_ROUTING) | (1 << NF_INET_FORWARD)); } static struct nft_expr_type nft_osf_type; static const struct nft_expr_ops nft_osf_op = { .eval = nft_osf_eval, .size = NFT_EXPR_SIZE(sizeof(struct nft_osf)), .init = nft_osf_init, .dump = nft_osf_dump, .type = &nft_osf_type, .validate = nft_osf_validate, }; static struct nft_expr_type nft_osf_type __read_mostly = { .ops = &nft_osf_op, .name = "osf", .owner = THIS_MODULE, .policy = nft_osf_policy, .maxattr = NFTA_OSF_MAX, }; static int __init nft_osf_module_init(void) { return nft_register_expr(&nft_osf_type); } static void __exit nft_osf_module_exit(void) { return nft_unregister_expr(&nft_osf_type); } module_init(nft_osf_module_init); module_exit(nft_osf_module_exit); MODULE_LICENSE("GPL"); MODULE_AUTHOR("Fernando Fernandez "); MODULE_ALIAS_NFT_EXPR("osf");