diff options
Diffstat (limited to 'net/openvswitch/conntrack.c')
-rw-r--r-- | net/openvswitch/conntrack.c | 744 |
1 files changed, 744 insertions, 0 deletions
diff --git a/net/openvswitch/conntrack.c b/net/openvswitch/conntrack.c new file mode 100644 index 0000000..886bd27 --- /dev/null +++ b/net/openvswitch/conntrack.c @@ -0,0 +1,744 @@ +/* + * Copyright (c) 2015 Nicira, Inc. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of version 2 of the GNU General Public + * License as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + */ + +#include <linux/module.h> +#include <linux/openvswitch.h> +#include <net/ip.h> +#include <net/netfilter/nf_conntrack_core.h> +#include <net/netfilter/nf_conntrack_helper.h> +#include <net/netfilter/nf_conntrack_labels.h> +#include <net/netfilter/nf_conntrack_zones.h> +#include <net/netfilter/ipv6/nf_defrag_ipv6.h> + +#include "datapath.h" +#include "conntrack.h" +#include "flow.h" +#include "flow_netlink.h" + +struct ovs_ct_len_tbl { + size_t maxlen; + size_t minlen; +}; + +/* Metadata mark for masked write to conntrack mark */ +struct md_mark { + u32 value; + u32 mask; +}; + +/* Metadata label for masked write to conntrack label. */ +struct md_label { + struct ovs_key_ct_label value; + struct ovs_key_ct_label mask; +}; + +/* Conntrack action context for execution. */ +struct ovs_conntrack_info { + struct nf_conntrack_helper *helper; + struct nf_conntrack_zone zone; + struct nf_conn *ct; + u32 flags; + u16 family; + struct md_mark mark; + struct md_label label; +}; + +static u16 key_to_nfproto(const struct sw_flow_key *key) +{ + switch (ntohs(key->eth.type)) { + case ETH_P_IP: + return NFPROTO_IPV4; + case ETH_P_IPV6: + return NFPROTO_IPV6; + default: + return NFPROTO_UNSPEC; + } +} + +/* Map SKB connection state into the values used by flow definition. */ +static u8 ovs_ct_get_state(enum ip_conntrack_info ctinfo) +{ + u8 ct_state = OVS_CS_F_TRACKED; + + switch (ctinfo) { + case IP_CT_ESTABLISHED_REPLY: + case IP_CT_RELATED_REPLY: + case IP_CT_NEW_REPLY: + ct_state |= OVS_CS_F_REPLY_DIR; + break; + default: + break; + } + + switch (ctinfo) { + case IP_CT_ESTABLISHED: + case IP_CT_ESTABLISHED_REPLY: + ct_state |= OVS_CS_F_ESTABLISHED; + break; + case IP_CT_RELATED: + case IP_CT_RELATED_REPLY: + ct_state |= OVS_CS_F_RELATED; + break; + case IP_CT_NEW: + case IP_CT_NEW_REPLY: + ct_state |= OVS_CS_F_NEW; + break; + default: + break; + } + + return ct_state; +} + +static void ovs_ct_get_label(const struct nf_conn *ct, + struct ovs_key_ct_label *label) +{ + struct nf_conn_labels *cl = ct ? nf_ct_labels_find(ct) : NULL; + + if (cl) { + size_t len = cl->words * sizeof(long); + + if (len > OVS_CT_LABEL_LEN) + len = OVS_CT_LABEL_LEN; + else if (len < OVS_CT_LABEL_LEN) + memset(label, 0, OVS_CT_LABEL_LEN); + memcpy(label, cl->bits, len); + } else { + memset(label, 0, OVS_CT_LABEL_LEN); + } +} + +static void __ovs_ct_update_key(struct sw_flow_key *key, u8 state, + const struct nf_conntrack_zone *zone, + const struct nf_conn *ct) +{ + key->ct.state = state; + key->ct.zone = zone->id; + key->ct.mark = ct ? ct->mark : 0; + ovs_ct_get_label(ct, &key->ct.label); +} + +/* Update 'key' based on skb->nfct. If 'post_ct' is true, then OVS has + * previously sent the packet to conntrack via the ct action. + */ +static void ovs_ct_update_key(const struct sk_buff *skb, + struct sw_flow_key *key, bool post_ct) +{ + const struct nf_conntrack_zone *zone = &nf_ct_zone_dflt; + enum ip_conntrack_info ctinfo; + struct nf_conn *ct; + u8 state = 0; + + ct = nf_ct_get(skb, &ctinfo); + if (ct) { + state = ovs_ct_get_state(ctinfo); + if (ct->master) + state |= OVS_CS_F_RELATED; + zone = nf_ct_zone(ct); + } else if (post_ct) { + state = OVS_CS_F_TRACKED | OVS_CS_F_INVALID; + } + __ovs_ct_update_key(key, state, zone, ct); +} + +void ovs_ct_fill_key(const struct sk_buff *skb, struct sw_flow_key *key) +{ + ovs_ct_update_key(skb, key, false); +} + +int ovs_ct_put_key(const struct sw_flow_key *key, struct sk_buff *skb) +{ + if (nla_put_u8(skb, OVS_KEY_ATTR_CT_STATE, key->ct.state)) + return -EMSGSIZE; + + if (IS_ENABLED(CONFIG_NF_CONNTRACK_ZONES) && + nla_put_u16(skb, OVS_KEY_ATTR_CT_ZONE, key->ct.zone)) + return -EMSGSIZE; + + if (IS_ENABLED(CONFIG_NF_CONNTRACK_MARK) && + nla_put_u32(skb, OVS_KEY_ATTR_CT_MARK, key->ct.mark)) + return -EMSGSIZE; + + if (IS_ENABLED(CONFIG_NF_CONNTRACK_LABELS) && + nla_put(skb, OVS_KEY_ATTR_CT_LABEL, sizeof(key->ct.label), + &key->ct.label)) + return -EMSGSIZE; + + return 0; +} + +static int ovs_ct_set_mark(struct sk_buff *skb, struct sw_flow_key *key, + u32 ct_mark, u32 mask) +{ + enum ip_conntrack_info ctinfo; + struct nf_conn *ct; + u32 new_mark; + + if (!IS_ENABLED(CONFIG_NF_CONNTRACK_MARK)) + return -ENOTSUPP; + + /* The connection could be invalid, in which case set_mark is no-op. */ + ct = nf_ct_get(skb, &ctinfo); + if (!ct) + return 0; + + new_mark = ct_mark | (ct->mark & ~(mask)); + if (ct->mark != new_mark) { + ct->mark = new_mark; + nf_conntrack_event_cache(IPCT_MARK, ct); + key->ct.mark = new_mark; + } + + return 0; +} + +static int ovs_ct_set_label(struct sk_buff *skb, struct sw_flow_key *key, + const struct ovs_key_ct_label *label, + const struct ovs_key_ct_label *mask) +{ + enum ip_conntrack_info ctinfo; + struct nf_conn_labels *cl; + struct nf_conn *ct; + int err; + + if (!IS_ENABLED(CONFIG_NF_CONNTRACK_LABELS)) + return -ENOTSUPP; + + /* The connection could be invalid, in which case set_label is no-op.*/ + ct = nf_ct_get(skb, &ctinfo); + if (!ct) + return 0; + + cl = nf_ct_labels_find(ct); + if (!cl) { + nf_ct_labels_ext_add(ct); + cl = nf_ct_labels_find(ct); + } + if (!cl || cl->words * sizeof(long) < OVS_CT_LABEL_LEN) + return -ENOSPC; + + err = nf_connlabels_replace(ct, (u32 *)label, (u32 *)mask, + OVS_CT_LABEL_LEN / sizeof(u32)); + if (err) + return err; + + ovs_ct_get_label(ct, &key->ct.label); + return 0; +} + +/* 'skb' should already be pulled to nh_ofs. */ +static int ovs_ct_helper(struct sk_buff *skb, u16 proto) +{ + const struct nf_conntrack_helper *helper; + const struct nf_conn_help *help; + enum ip_conntrack_info ctinfo; + unsigned int protoff; + struct nf_conn *ct; + + ct = nf_ct_get(skb, &ctinfo); + if (!ct || ctinfo == IP_CT_RELATED_REPLY) + return NF_ACCEPT; + + help = nfct_help(ct); + if (!help) + return NF_ACCEPT; + + helper = rcu_dereference(help->helper); + if (!helper) + return NF_ACCEPT; + + switch (proto) { + case NFPROTO_IPV4: + protoff = ip_hdrlen(skb); + break; + case NFPROTO_IPV6: { + u8 nexthdr = ipv6_hdr(skb)->nexthdr; + __be16 frag_off; + + protoff = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), + &nexthdr, &frag_off); + if (protoff < 0 || (frag_off & htons(~0x7)) != 0) { + pr_debug("proto header not found\n"); + return NF_ACCEPT; + } + break; + } + default: + WARN_ONCE(1, "helper invoked on non-IP family!"); + return NF_DROP; + } + + return helper->help(skb, protoff, ct, ctinfo); +} + +static int handle_fragments(struct net *net, struct sw_flow_key *key, + u16 zone, struct sk_buff *skb) +{ + struct ovs_skb_cb ovs_cb = *OVS_CB(skb); + + if (key->eth.type == htons(ETH_P_IP)) { + enum ip_defrag_users user = IP_DEFRAG_CONNTRACK_IN + zone; + int err; + + memset(IPCB(skb), 0, sizeof(struct inet_skb_parm)); + err = ip_defrag(skb, user); + if (err) + return err; + + ovs_cb.mru = IPCB(skb)->frag_max_size; + } else if (key->eth.type == htons(ETH_P_IPV6)) { +#if IS_ENABLED(CONFIG_NF_DEFRAG_IPV6) + enum ip6_defrag_users user = IP6_DEFRAG_CONNTRACK_IN + zone; + struct sk_buff *reasm; + + memset(IP6CB(skb), 0, sizeof(struct inet6_skb_parm)); + reasm = nf_ct_frag6_gather(skb, user); + if (!reasm) + return -EINPROGRESS; + + if (skb == reasm) + return -EINVAL; + + key->ip.proto = ipv6_hdr(reasm)->nexthdr; + skb_morph(skb, reasm); + consume_skb(reasm); + ovs_cb.mru = IP6CB(skb)->frag_max_size; +#else + return -EPFNOSUPPORT; +#endif + } else { + return -EPFNOSUPPORT; + } + + key->ip.frag = OVS_FRAG_TYPE_NONE; + skb_clear_hash(skb); + skb->ignore_df = 1; + *OVS_CB(skb) = ovs_cb; + + return 0; +} + +static struct nf_conntrack_expect * +ovs_ct_expect_find(struct net *net, const struct nf_conntrack_zone *zone, + u16 proto, const struct sk_buff *skb) +{ + struct nf_conntrack_tuple tuple; + + if (!nf_ct_get_tuplepr(skb, skb_network_offset(skb), proto, &tuple)) + return NULL; + return __nf_ct_expect_find(net, zone, &tuple); +} + +/* Determine whether skb->nfct is equal to the result of conntrack lookup. */ +static bool skb_nfct_cached(const struct net *net, const struct sk_buff *skb, + const struct ovs_conntrack_info *info) +{ + enum ip_conntrack_info ctinfo; + struct nf_conn *ct; + + ct = nf_ct_get(skb, &ctinfo); + if (!ct) + return false; + if (!net_eq(net, read_pnet(&ct->ct_net))) + return false; + if (!nf_ct_zone_equal_any(info->ct, nf_ct_zone(ct))) + return false; + if (info->helper) { + struct nf_conn_help *help; + + help = nf_ct_ext_find(ct, NF_CT_EXT_HELPER); + if (help && rcu_access_pointer(help->helper) != info->helper) + return false; + } + + return true; +} + +static int __ovs_ct_lookup(struct net *net, const struct sw_flow_key *key, + const struct ovs_conntrack_info *info, + struct sk_buff *skb) +{ + /* If we are recirculating packets to match on conntrack fields and + * committing with a separate conntrack action, then we don't need to + * actually run the packet through conntrack twice unless it's for a + * different zone. + */ + if (!skb_nfct_cached(net, skb, info)) { + struct nf_conn *tmpl = info->ct; + + /* Associate skb with specified zone. */ + if (tmpl) { + if (skb->nfct) + nf_conntrack_put(skb->nfct); + nf_conntrack_get(&tmpl->ct_general); + skb->nfct = &tmpl->ct_general; + skb->nfctinfo = IP_CT_NEW; + } + + if (nf_conntrack_in(net, info->family, NF_INET_PRE_ROUTING, + skb) != NF_ACCEPT) + return -ENOENT; + + if (ovs_ct_helper(skb, info->family) != NF_ACCEPT) { + WARN_ONCE(1, "helper rejected packet"); + return -EINVAL; + } + } + + return 0; +} + +/* Lookup connection and read fields into key. */ +static int ovs_ct_lookup(struct net *net, struct sw_flow_key *key, + const struct ovs_conntrack_info *info, + struct sk_buff *skb) +{ + struct nf_conntrack_expect *exp; + + exp = ovs_ct_expect_find(net, &info->zone, info->family, skb); + if (exp) { + u8 state; + + state = OVS_CS_F_TRACKED | OVS_CS_F_NEW | OVS_CS_F_RELATED; + __ovs_ct_update_key(key, state, &info->zone, exp->master); + } else { + int err; + + err = __ovs_ct_lookup(net, key, info, skb); + if (err) + return err; + + ovs_ct_update_key(skb, key, true); + } + + return 0; +} + +/* Lookup connection and confirm if unconfirmed. */ +static int ovs_ct_commit(struct net *net, struct sw_flow_key *key, + const struct ovs_conntrack_info *info, + struct sk_buff *skb) +{ + u8 state; + int err; + + state = key->ct.state; + if (key->ct.zone == info->zone.id && + ((state & OVS_CS_F_TRACKED) && !(state & OVS_CS_F_NEW))) { + /* Previous lookup has shown that this connection is already + * tracked and committed. Skip committing. + */ + return 0; + } + + err = __ovs_ct_lookup(net, key, info, skb); + if (err) + return err; + if (nf_conntrack_confirm(skb) != NF_ACCEPT) + return -EINVAL; + + ovs_ct_update_key(skb, key, true); + + return 0; +} + +static bool label_nonzero(const struct ovs_key_ct_label *label) +{ + size_t i; + + for (i = 0; i < sizeof(*label); i++) + if (label->ct_label[i]) + return true; + + return false; +} + +int ovs_ct_execute(struct net *net, struct sk_buff *skb, + struct sw_flow_key *key, + const struct ovs_conntrack_info *info) +{ + int nh_ofs; + int err; + + /* The conntrack module expects to be working at L3. */ + nh_ofs = skb_network_offset(skb); + skb_pull(skb, nh_ofs); + + if (key->ip.frag != OVS_FRAG_TYPE_NONE) { + err = handle_fragments(net, key, info->zone.id, skb); + if (err) + return err; + } + + if (info->flags & OVS_CT_F_COMMIT) + err = ovs_ct_commit(net, key, info, skb); + else + err = ovs_ct_lookup(net, key, info, skb); + if (err) + goto err; + + if (info->mark.mask) { + err = ovs_ct_set_mark(skb, key, info->mark.value, + info->mark.mask); + if (err) + goto err; + } + if (label_nonzero(&info->label.mask)) + err = ovs_ct_set_label(skb, key, &info->label.value, + &info->label.mask); +err: + skb_push(skb, nh_ofs); + return err; +} + +static int ovs_ct_add_helper(struct ovs_conntrack_info *info, const char *name, + const struct sw_flow_key *key, bool log) +{ + struct nf_conntrack_helper *helper; + struct nf_conn_help *help; + + helper = nf_conntrack_helper_try_module_get(name, info->family, + key->ip.proto); + if (!helper) { + OVS_NLERR(log, "Unknown helper \"%s\"", name); + return -EINVAL; + } + + help = nf_ct_helper_ext_add(info->ct, helper, GFP_KERNEL); + if (!help) { + module_put(helper->me); + return -ENOMEM; + } + + rcu_assign_pointer(help->helper, helper); + info->helper = helper; + return 0; +} + +static const struct ovs_ct_len_tbl ovs_ct_attr_lens[OVS_CT_ATTR_MAX + 1] = { + [OVS_CT_ATTR_FLAGS] = { .minlen = sizeof(u32), + .maxlen = sizeof(u32) }, + [OVS_CT_ATTR_ZONE] = { .minlen = sizeof(u16), + .maxlen = sizeof(u16) }, + [OVS_CT_ATTR_MARK] = { .minlen = sizeof(struct md_mark), + .maxlen = sizeof(struct md_mark) }, + [OVS_CT_ATTR_LABEL] = { .minlen = sizeof(struct md_label), + .maxlen = sizeof(struct md_label) }, + [OVS_CT_ATTR_HELPER] = { .minlen = 1, + .maxlen = NF_CT_HELPER_NAME_LEN } +}; + +static int parse_ct(const struct nlattr *attr, struct ovs_conntrack_info *info, + const char **helper, bool log) +{ + struct nlattr *a; + int rem; + + nla_for_each_nested(a, attr, rem) { + int type = nla_type(a); + int maxlen = ovs_ct_attr_lens[type].maxlen; + int minlen = ovs_ct_attr_lens[type].minlen; + + if (type > OVS_CT_ATTR_MAX) { + OVS_NLERR(log, + "Unknown conntrack attr (type=%d, max=%d)", + type, OVS_CT_ATTR_MAX); + return -EINVAL; + } + if (nla_len(a) < minlen || nla_len(a) > maxlen) { + OVS_NLERR(log, + "Conntrack attr type has unexpected length (type=%d, length=%d, expected=%d)", + type, nla_len(a), maxlen); + return -EINVAL; + } + + switch (type) { + case OVS_CT_ATTR_FLAGS: + info->flags = nla_get_u32(a); + break; +#ifdef CONFIG_NF_CONNTRACK_ZONES + case OVS_CT_ATTR_ZONE: + info->zone.id = nla_get_u16(a); + break; +#endif +#ifdef CONFIG_NF_CONNTRACK_MARK + case OVS_CT_ATTR_MARK: { + struct md_mark *mark = nla_data(a); + + info->mark = *mark; + break; + } +#endif +#ifdef CONFIG_NF_CONNTRACK_LABELS + case OVS_CT_ATTR_LABEL: { + struct md_label *label = nla_data(a); + + info->label = *label; + break; + } +#endif + case OVS_CT_ATTR_HELPER: + *helper = nla_data(a); + if (!memchr(*helper, '\0', nla_len(a))) { + OVS_NLERR(log, "Invalid conntrack helper"); + return -EINVAL; + } + break; + default: + OVS_NLERR(log, "Unknown conntrack attr (%d)", + type); + return -EINVAL; + } + } + + if (rem > 0) { + OVS_NLERR(log, "Conntrack attr has %d unknown bytes", rem); + return -EINVAL; + } + + return 0; +} + +bool ovs_ct_verify(struct net *net, enum ovs_key_attr attr) +{ + if (attr == OVS_KEY_ATTR_CT_STATE) + return true; + if (IS_ENABLED(CONFIG_NF_CONNTRACK_ZONES) && + attr == OVS_KEY_ATTR_CT_ZONE) + return true; + if (IS_ENABLED(CONFIG_NF_CONNTRACK_MARK) && + attr == OVS_KEY_ATTR_CT_MARK) + return true; + if (IS_ENABLED(CONFIG_NF_CONNTRACK_LABELS) && + attr == OVS_KEY_ATTR_CT_LABEL) { + struct ovs_net *ovs_net = net_generic(net, ovs_net_id); + + return ovs_net->xt_label; + } + + return false; +} + +int ovs_ct_copy_action(struct net *net, const struct nlattr *attr, + const struct sw_flow_key *key, + struct sw_flow_actions **sfa, bool log) +{ + struct ovs_conntrack_info ct_info; + const char *helper = NULL; + u16 family; + int err; + + family = key_to_nfproto(key); + if (family == NFPROTO_UNSPEC) { + OVS_NLERR(log, "ct family unspecified"); + return -EINVAL; + } + + memset(&ct_info, 0, sizeof(ct_info)); + ct_info.family = family; + + nf_ct_zone_init(&ct_info.zone, NF_CT_DEFAULT_ZONE_ID, + NF_CT_DEFAULT_ZONE_DIR, 0); + + err = parse_ct(attr, &ct_info, &helper, log); + if (err) + return err; + + /* Set up template for tracking connections in specific zones. */ + ct_info.ct = nf_ct_tmpl_alloc(net, &ct_info.zone, GFP_KERNEL); + if (!ct_info.ct) { + OVS_NLERR(log, "Failed to allocate conntrack template"); + return -ENOMEM; + } + if (helper) { + err = ovs_ct_add_helper(&ct_info, helper, key, log); + if (err) + goto err_free_ct; + } + + err = ovs_nla_add_action(sfa, OVS_ACTION_ATTR_CT, &ct_info, + sizeof(ct_info), log); + if (err) + goto err_free_ct; + + __set_bit(IPS_CONFIRMED_BIT, &ct_info.ct->status); + nf_conntrack_get(&ct_info.ct->ct_general); + return 0; +err_free_ct: + nf_conntrack_free(ct_info.ct); + return err; +} + +int ovs_ct_action_to_attr(const struct ovs_conntrack_info *ct_info, + struct sk_buff *skb) +{ + struct nlattr *start; + + start = nla_nest_start(skb, OVS_ACTION_ATTR_CT); + if (!start) + return -EMSGSIZE; + + if (nla_put_u32(skb, OVS_CT_ATTR_FLAGS, ct_info->flags)) + return -EMSGSIZE; + if (IS_ENABLED(CONFIG_NF_CONNTRACK_ZONES) && + nla_put_u16(skb, OVS_CT_ATTR_ZONE, ct_info->zone.id)) + return -EMSGSIZE; + if (IS_ENABLED(CONFIG_NF_CONNTRACK_MARK) && + nla_put(skb, OVS_CT_ATTR_MARK, sizeof(ct_info->mark), + &ct_info->mark)) + return -EMSGSIZE; + if (IS_ENABLED(CONFIG_NF_CONNTRACK_LABELS) && + nla_put(skb, OVS_CT_ATTR_LABEL, sizeof(ct_info->label), + &ct_info->label)) + return -EMSGSIZE; + if (ct_info->helper) { + if (nla_put_string(skb, OVS_CT_ATTR_HELPER, + ct_info->helper->name)) + return -EMSGSIZE; + } + + nla_nest_end(skb, start); + + return 0; +} + +void ovs_ct_free_action(const struct nlattr *a) +{ + struct ovs_conntrack_info *ct_info = nla_data(a); + + if (ct_info->helper) + module_put(ct_info->helper->me); + if (ct_info->ct) + nf_ct_put(ct_info->ct); +} + +void ovs_ct_init(struct net *net) +{ + unsigned int n_bits = sizeof(struct ovs_key_ct_label) * BITS_PER_BYTE; + struct ovs_net *ovs_net = net_generic(net, ovs_net_id); + + if (nf_connlabels_get(net, n_bits)) { + ovs_net->xt_label = false; + OVS_NLERR(true, "Failed to set connlabel length"); + } else { + ovs_net->xt_label = true; + } +} + +void ovs_ct_exit(struct net *net) +{ + struct ovs_net *ovs_net = net_generic(net, ovs_net_id); + + if (ovs_net->xt_label) + nf_connlabels_put(net); +} |