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511 lines
13 KiB
511 lines
13 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* net/psample/psample.c - Netlink channel for packet sampling |
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* Copyright (c) 2017 Yotam Gigi <[email protected]> |
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*/ |
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|
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#include <linux/types.h> |
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#include <linux/kernel.h> |
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#include <linux/skbuff.h> |
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#include <linux/module.h> |
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#include <linux/timekeeping.h> |
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#include <net/net_namespace.h> |
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#include <net/sock.h> |
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#include <net/netlink.h> |
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#include <net/genetlink.h> |
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#include <net/psample.h> |
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#include <linux/spinlock.h> |
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#include <net/ip_tunnels.h> |
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#include <net/dst_metadata.h> |
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#define PSAMPLE_MAX_PACKET_SIZE 0xffff |
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static LIST_HEAD(psample_groups_list); |
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static DEFINE_SPINLOCK(psample_groups_lock); |
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/* multicast groups */ |
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enum psample_nl_multicast_groups { |
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PSAMPLE_NL_MCGRP_CONFIG, |
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PSAMPLE_NL_MCGRP_SAMPLE, |
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}; |
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static const struct genl_multicast_group psample_nl_mcgrps[] = { |
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[PSAMPLE_NL_MCGRP_CONFIG] = { .name = PSAMPLE_NL_MCGRP_CONFIG_NAME }, |
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[PSAMPLE_NL_MCGRP_SAMPLE] = { .name = PSAMPLE_NL_MCGRP_SAMPLE_NAME }, |
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}; |
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static struct genl_family psample_nl_family __ro_after_init; |
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static int psample_group_nl_fill(struct sk_buff *msg, |
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struct psample_group *group, |
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enum psample_command cmd, u32 portid, u32 seq, |
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int flags) |
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{ |
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void *hdr; |
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int ret; |
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hdr = genlmsg_put(msg, portid, seq, &psample_nl_family, flags, cmd); |
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if (!hdr) |
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return -EMSGSIZE; |
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ret = nla_put_u32(msg, PSAMPLE_ATTR_SAMPLE_GROUP, group->group_num); |
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if (ret < 0) |
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goto error; |
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ret = nla_put_u32(msg, PSAMPLE_ATTR_GROUP_REFCOUNT, group->refcount); |
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if (ret < 0) |
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goto error; |
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ret = nla_put_u32(msg, PSAMPLE_ATTR_GROUP_SEQ, group->seq); |
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if (ret < 0) |
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goto error; |
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genlmsg_end(msg, hdr); |
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return 0; |
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error: |
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genlmsg_cancel(msg, hdr); |
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return -EMSGSIZE; |
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} |
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static int psample_nl_cmd_get_group_dumpit(struct sk_buff *msg, |
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struct netlink_callback *cb) |
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{ |
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struct psample_group *group; |
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int start = cb->args[0]; |
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int idx = 0; |
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int err; |
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spin_lock_bh(&psample_groups_lock); |
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list_for_each_entry(group, &psample_groups_list, list) { |
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if (!net_eq(group->net, sock_net(msg->sk))) |
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continue; |
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if (idx < start) { |
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idx++; |
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continue; |
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} |
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err = psample_group_nl_fill(msg, group, PSAMPLE_CMD_NEW_GROUP, |
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NETLINK_CB(cb->skb).portid, |
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cb->nlh->nlmsg_seq, NLM_F_MULTI); |
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if (err) |
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break; |
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idx++; |
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} |
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spin_unlock_bh(&psample_groups_lock); |
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cb->args[0] = idx; |
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return msg->len; |
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} |
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static const struct genl_small_ops psample_nl_ops[] = { |
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{ |
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.cmd = PSAMPLE_CMD_GET_GROUP, |
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.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, |
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.dumpit = psample_nl_cmd_get_group_dumpit, |
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/* can be retrieved by unprivileged users */ |
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} |
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}; |
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static struct genl_family psample_nl_family __ro_after_init = { |
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.name = PSAMPLE_GENL_NAME, |
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.version = PSAMPLE_GENL_VERSION, |
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.maxattr = PSAMPLE_ATTR_MAX, |
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.netnsok = true, |
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.module = THIS_MODULE, |
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.mcgrps = psample_nl_mcgrps, |
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.small_ops = psample_nl_ops, |
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.n_small_ops = ARRAY_SIZE(psample_nl_ops), |
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.n_mcgrps = ARRAY_SIZE(psample_nl_mcgrps), |
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}; |
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static void psample_group_notify(struct psample_group *group, |
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enum psample_command cmd) |
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{ |
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struct sk_buff *msg; |
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int err; |
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msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC); |
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if (!msg) |
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return; |
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err = psample_group_nl_fill(msg, group, cmd, 0, 0, NLM_F_MULTI); |
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if (!err) |
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genlmsg_multicast_netns(&psample_nl_family, group->net, msg, 0, |
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PSAMPLE_NL_MCGRP_CONFIG, GFP_ATOMIC); |
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else |
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nlmsg_free(msg); |
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} |
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static struct psample_group *psample_group_create(struct net *net, |
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u32 group_num) |
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{ |
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struct psample_group *group; |
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group = kzalloc(sizeof(*group), GFP_ATOMIC); |
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if (!group) |
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return NULL; |
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group->net = net; |
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group->group_num = group_num; |
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list_add_tail(&group->list, &psample_groups_list); |
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psample_group_notify(group, PSAMPLE_CMD_NEW_GROUP); |
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return group; |
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} |
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static void psample_group_destroy(struct psample_group *group) |
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{ |
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psample_group_notify(group, PSAMPLE_CMD_DEL_GROUP); |
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list_del(&group->list); |
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kfree_rcu(group, rcu); |
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} |
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static struct psample_group * |
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psample_group_lookup(struct net *net, u32 group_num) |
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{ |
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struct psample_group *group; |
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list_for_each_entry(group, &psample_groups_list, list) |
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if ((group->group_num == group_num) && (group->net == net)) |
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return group; |
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return NULL; |
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} |
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struct psample_group *psample_group_get(struct net *net, u32 group_num) |
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{ |
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struct psample_group *group; |
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spin_lock_bh(&psample_groups_lock); |
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group = psample_group_lookup(net, group_num); |
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if (!group) { |
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group = psample_group_create(net, group_num); |
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if (!group) |
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goto out; |
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} |
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group->refcount++; |
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out: |
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spin_unlock_bh(&psample_groups_lock); |
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return group; |
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} |
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EXPORT_SYMBOL_GPL(psample_group_get); |
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void psample_group_take(struct psample_group *group) |
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{ |
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spin_lock_bh(&psample_groups_lock); |
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group->refcount++; |
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spin_unlock_bh(&psample_groups_lock); |
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} |
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EXPORT_SYMBOL_GPL(psample_group_take); |
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void psample_group_put(struct psample_group *group) |
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{ |
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spin_lock_bh(&psample_groups_lock); |
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if (--group->refcount == 0) |
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psample_group_destroy(group); |
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spin_unlock_bh(&psample_groups_lock); |
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} |
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EXPORT_SYMBOL_GPL(psample_group_put); |
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#ifdef CONFIG_INET |
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static int __psample_ip_tun_to_nlattr(struct sk_buff *skb, |
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struct ip_tunnel_info *tun_info) |
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{ |
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unsigned short tun_proto = ip_tunnel_info_af(tun_info); |
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const void *tun_opts = ip_tunnel_info_opts(tun_info); |
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const struct ip_tunnel_key *tun_key = &tun_info->key; |
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int tun_opts_len = tun_info->options_len; |
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if (tun_key->tun_flags & TUNNEL_KEY && |
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nla_put_be64(skb, PSAMPLE_TUNNEL_KEY_ATTR_ID, tun_key->tun_id, |
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PSAMPLE_TUNNEL_KEY_ATTR_PAD)) |
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return -EMSGSIZE; |
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if (tun_info->mode & IP_TUNNEL_INFO_BRIDGE && |
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nla_put_flag(skb, PSAMPLE_TUNNEL_KEY_ATTR_IPV4_INFO_BRIDGE)) |
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return -EMSGSIZE; |
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switch (tun_proto) { |
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case AF_INET: |
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if (tun_key->u.ipv4.src && |
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nla_put_in_addr(skb, PSAMPLE_TUNNEL_KEY_ATTR_IPV4_SRC, |
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tun_key->u.ipv4.src)) |
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return -EMSGSIZE; |
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if (tun_key->u.ipv4.dst && |
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nla_put_in_addr(skb, PSAMPLE_TUNNEL_KEY_ATTR_IPV4_DST, |
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tun_key->u.ipv4.dst)) |
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return -EMSGSIZE; |
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break; |
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case AF_INET6: |
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if (!ipv6_addr_any(&tun_key->u.ipv6.src) && |
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nla_put_in6_addr(skb, PSAMPLE_TUNNEL_KEY_ATTR_IPV6_SRC, |
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&tun_key->u.ipv6.src)) |
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return -EMSGSIZE; |
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if (!ipv6_addr_any(&tun_key->u.ipv6.dst) && |
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nla_put_in6_addr(skb, PSAMPLE_TUNNEL_KEY_ATTR_IPV6_DST, |
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&tun_key->u.ipv6.dst)) |
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return -EMSGSIZE; |
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break; |
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} |
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if (tun_key->tos && |
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nla_put_u8(skb, PSAMPLE_TUNNEL_KEY_ATTR_TOS, tun_key->tos)) |
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return -EMSGSIZE; |
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if (nla_put_u8(skb, PSAMPLE_TUNNEL_KEY_ATTR_TTL, tun_key->ttl)) |
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return -EMSGSIZE; |
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if ((tun_key->tun_flags & TUNNEL_DONT_FRAGMENT) && |
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nla_put_flag(skb, PSAMPLE_TUNNEL_KEY_ATTR_DONT_FRAGMENT)) |
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return -EMSGSIZE; |
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if ((tun_key->tun_flags & TUNNEL_CSUM) && |
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nla_put_flag(skb, PSAMPLE_TUNNEL_KEY_ATTR_CSUM)) |
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return -EMSGSIZE; |
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if (tun_key->tp_src && |
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nla_put_be16(skb, PSAMPLE_TUNNEL_KEY_ATTR_TP_SRC, tun_key->tp_src)) |
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return -EMSGSIZE; |
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if (tun_key->tp_dst && |
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nla_put_be16(skb, PSAMPLE_TUNNEL_KEY_ATTR_TP_DST, tun_key->tp_dst)) |
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return -EMSGSIZE; |
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if ((tun_key->tun_flags & TUNNEL_OAM) && |
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nla_put_flag(skb, PSAMPLE_TUNNEL_KEY_ATTR_OAM)) |
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return -EMSGSIZE; |
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if (tun_opts_len) { |
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if (tun_key->tun_flags & TUNNEL_GENEVE_OPT && |
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nla_put(skb, PSAMPLE_TUNNEL_KEY_ATTR_GENEVE_OPTS, |
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tun_opts_len, tun_opts)) |
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return -EMSGSIZE; |
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else if (tun_key->tun_flags & TUNNEL_ERSPAN_OPT && |
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nla_put(skb, PSAMPLE_TUNNEL_KEY_ATTR_ERSPAN_OPTS, |
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tun_opts_len, tun_opts)) |
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return -EMSGSIZE; |
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} |
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return 0; |
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} |
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static int psample_ip_tun_to_nlattr(struct sk_buff *skb, |
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struct ip_tunnel_info *tun_info) |
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{ |
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struct nlattr *nla; |
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int err; |
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nla = nla_nest_start_noflag(skb, PSAMPLE_ATTR_TUNNEL); |
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if (!nla) |
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return -EMSGSIZE; |
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err = __psample_ip_tun_to_nlattr(skb, tun_info); |
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if (err) { |
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nla_nest_cancel(skb, nla); |
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return err; |
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} |
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nla_nest_end(skb, nla); |
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return 0; |
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} |
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static int psample_tunnel_meta_len(struct ip_tunnel_info *tun_info) |
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{ |
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unsigned short tun_proto = ip_tunnel_info_af(tun_info); |
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const struct ip_tunnel_key *tun_key = &tun_info->key; |
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int tun_opts_len = tun_info->options_len; |
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int sum = nla_total_size(0); /* PSAMPLE_ATTR_TUNNEL */ |
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if (tun_key->tun_flags & TUNNEL_KEY) |
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sum += nla_total_size_64bit(sizeof(u64)); |
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if (tun_info->mode & IP_TUNNEL_INFO_BRIDGE) |
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sum += nla_total_size(0); |
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switch (tun_proto) { |
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case AF_INET: |
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if (tun_key->u.ipv4.src) |
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sum += nla_total_size(sizeof(u32)); |
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if (tun_key->u.ipv4.dst) |
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sum += nla_total_size(sizeof(u32)); |
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break; |
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case AF_INET6: |
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if (!ipv6_addr_any(&tun_key->u.ipv6.src)) |
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sum += nla_total_size(sizeof(struct in6_addr)); |
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if (!ipv6_addr_any(&tun_key->u.ipv6.dst)) |
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sum += nla_total_size(sizeof(struct in6_addr)); |
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break; |
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} |
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if (tun_key->tos) |
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sum += nla_total_size(sizeof(u8)); |
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sum += nla_total_size(sizeof(u8)); /* TTL */ |
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if (tun_key->tun_flags & TUNNEL_DONT_FRAGMENT) |
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sum += nla_total_size(0); |
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if (tun_key->tun_flags & TUNNEL_CSUM) |
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sum += nla_total_size(0); |
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if (tun_key->tp_src) |
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sum += nla_total_size(sizeof(u16)); |
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if (tun_key->tp_dst) |
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sum += nla_total_size(sizeof(u16)); |
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if (tun_key->tun_flags & TUNNEL_OAM) |
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sum += nla_total_size(0); |
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if (tun_opts_len) { |
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if (tun_key->tun_flags & TUNNEL_GENEVE_OPT) |
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sum += nla_total_size(tun_opts_len); |
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else if (tun_key->tun_flags & TUNNEL_ERSPAN_OPT) |
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sum += nla_total_size(tun_opts_len); |
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} |
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return sum; |
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} |
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#endif |
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void psample_sample_packet(struct psample_group *group, struct sk_buff *skb, |
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u32 sample_rate, const struct psample_metadata *md) |
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{ |
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ktime_t tstamp = ktime_get_real(); |
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int out_ifindex = md->out_ifindex; |
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int in_ifindex = md->in_ifindex; |
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u32 trunc_size = md->trunc_size; |
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#ifdef CONFIG_INET |
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struct ip_tunnel_info *tun_info; |
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#endif |
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struct sk_buff *nl_skb; |
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int data_len; |
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int meta_len; |
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void *data; |
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int ret; |
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meta_len = (in_ifindex ? nla_total_size(sizeof(u16)) : 0) + |
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(out_ifindex ? nla_total_size(sizeof(u16)) : 0) + |
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(md->out_tc_valid ? nla_total_size(sizeof(u16)) : 0) + |
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(md->out_tc_occ_valid ? nla_total_size_64bit(sizeof(u64)) : 0) + |
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(md->latency_valid ? nla_total_size_64bit(sizeof(u64)) : 0) + |
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nla_total_size(sizeof(u32)) + /* sample_rate */ |
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nla_total_size(sizeof(u32)) + /* orig_size */ |
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nla_total_size(sizeof(u32)) + /* group_num */ |
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nla_total_size(sizeof(u32)) + /* seq */ |
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nla_total_size_64bit(sizeof(u64)) + /* timestamp */ |
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nla_total_size(sizeof(u16)); /* protocol */ |
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#ifdef CONFIG_INET |
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tun_info = skb_tunnel_info(skb); |
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if (tun_info) |
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meta_len += psample_tunnel_meta_len(tun_info); |
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#endif |
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data_len = min(skb->len, trunc_size); |
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if (meta_len + nla_total_size(data_len) > PSAMPLE_MAX_PACKET_SIZE) |
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data_len = PSAMPLE_MAX_PACKET_SIZE - meta_len - NLA_HDRLEN |
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- NLA_ALIGNTO; |
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nl_skb = genlmsg_new(meta_len + nla_total_size(data_len), GFP_ATOMIC); |
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if (unlikely(!nl_skb)) |
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return; |
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data = genlmsg_put(nl_skb, 0, 0, &psample_nl_family, 0, |
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PSAMPLE_CMD_SAMPLE); |
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if (unlikely(!data)) |
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goto error; |
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if (in_ifindex) { |
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ret = nla_put_u16(nl_skb, PSAMPLE_ATTR_IIFINDEX, in_ifindex); |
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if (unlikely(ret < 0)) |
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goto error; |
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} |
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if (out_ifindex) { |
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ret = nla_put_u16(nl_skb, PSAMPLE_ATTR_OIFINDEX, out_ifindex); |
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if (unlikely(ret < 0)) |
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goto error; |
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} |
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ret = nla_put_u32(nl_skb, PSAMPLE_ATTR_SAMPLE_RATE, sample_rate); |
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if (unlikely(ret < 0)) |
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goto error; |
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ret = nla_put_u32(nl_skb, PSAMPLE_ATTR_ORIGSIZE, skb->len); |
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if (unlikely(ret < 0)) |
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goto error; |
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ret = nla_put_u32(nl_skb, PSAMPLE_ATTR_SAMPLE_GROUP, group->group_num); |
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if (unlikely(ret < 0)) |
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goto error; |
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ret = nla_put_u32(nl_skb, PSAMPLE_ATTR_GROUP_SEQ, group->seq++); |
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if (unlikely(ret < 0)) |
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goto error; |
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if (md->out_tc_valid) { |
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ret = nla_put_u16(nl_skb, PSAMPLE_ATTR_OUT_TC, md->out_tc); |
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if (unlikely(ret < 0)) |
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goto error; |
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} |
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if (md->out_tc_occ_valid) { |
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ret = nla_put_u64_64bit(nl_skb, PSAMPLE_ATTR_OUT_TC_OCC, |
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md->out_tc_occ, PSAMPLE_ATTR_PAD); |
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if (unlikely(ret < 0)) |
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goto error; |
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} |
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if (md->latency_valid) { |
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ret = nla_put_u64_64bit(nl_skb, PSAMPLE_ATTR_LATENCY, |
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md->latency, PSAMPLE_ATTR_PAD); |
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if (unlikely(ret < 0)) |
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goto error; |
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} |
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ret = nla_put_u64_64bit(nl_skb, PSAMPLE_ATTR_TIMESTAMP, |
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ktime_to_ns(tstamp), PSAMPLE_ATTR_PAD); |
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if (unlikely(ret < 0)) |
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goto error; |
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ret = nla_put_u16(nl_skb, PSAMPLE_ATTR_PROTO, |
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be16_to_cpu(skb->protocol)); |
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if (unlikely(ret < 0)) |
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goto error; |
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if (data_len) { |
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int nla_len = nla_total_size(data_len); |
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struct nlattr *nla; |
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nla = skb_put(nl_skb, nla_len); |
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nla->nla_type = PSAMPLE_ATTR_DATA; |
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nla->nla_len = nla_attr_size(data_len); |
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if (skb_copy_bits(skb, 0, nla_data(nla), data_len)) |
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goto error; |
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} |
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#ifdef CONFIG_INET |
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if (tun_info) { |
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ret = psample_ip_tun_to_nlattr(nl_skb, tun_info); |
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if (unlikely(ret < 0)) |
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goto error; |
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} |
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#endif |
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genlmsg_end(nl_skb, data); |
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genlmsg_multicast_netns(&psample_nl_family, group->net, nl_skb, 0, |
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PSAMPLE_NL_MCGRP_SAMPLE, GFP_ATOMIC); |
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return; |
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error: |
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pr_err_ratelimited("Could not create psample log message\n"); |
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nlmsg_free(nl_skb); |
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} |
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EXPORT_SYMBOL_GPL(psample_sample_packet); |
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|
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static int __init psample_module_init(void) |
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{ |
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return genl_register_family(&psample_nl_family); |
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} |
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|
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static void __exit psample_module_exit(void) |
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{ |
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genl_unregister_family(&psample_nl_family); |
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} |
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module_init(psample_module_init); |
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module_exit(psample_module_exit); |
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|
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MODULE_AUTHOR("Yotam Gigi <[email protected]>"); |
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MODULE_DESCRIPTION("netlink channel for packet sampling"); |
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MODULE_LICENSE("GPL v2");
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