5 files changed, 323 insertions, 0 deletions

diff --git a/net/Kconfig b/net/Kconfig
index 92ae1500d9e1..ce4aee69fc0d 100644
--- a/net/Kconfig
+++ b/net/Kconfig
@@ -390,6 +390,7 @@ source "net/9p/Kconfig"
 source "net/caif/Kconfig"
 source "net/ceph/Kconfig"
 source "net/nfc/Kconfig"
+source "net/psample/Kconfig"
 
 config LWTUNNEL
         bool "Network light weight tunnels"
diff --git a/net/Makefile b/net/Makefile
index 5d6e0e5ff7f8..7d41de48310e 100644
--- a/net/Makefile
+++ b/net/Makefile
@@ -70,6 +70,7 @@ obj-$(CONFIG_DNS_RESOLVER)	+= dns_resolver/
 obj-$(CONFIG_CEPH_LIB)          += ceph/
 obj-$(CONFIG_BATMAN_ADV)        += batman-adv/
 obj-$(CONFIG_NFC)               += nfc/
+obj-$(CONFIG_PSAMPLE)           += psample/
 obj-$(CONFIG_OPENVSWITCH)       += openvswitch/
 obj-$(CONFIG_VSOCKETS)  += vmw_vsock/
 obj-$(CONFIG_MPLS)              += mpls/
diff --git a/net/psample/Kconfig b/net/psample/Kconfig
new file mode 100644
index 000000000000..d850246a6059
--- /dev/null
+++ b/net/psample/Kconfig
@@ -0,0 +1,15 @@
+#
+# psample packet sampling configuration
+#
+
+menuconfig PSAMPLE
+        depends on NET
+        tristate "Packet-sampling netlink channel"
+        default n
+        help
+          Say Y here to add support for packet-sampling netlink channel
+          This netlink channel allows transferring packets alongside some
+          metadata to userspace.
+
+          To compile this support as a module, choose M here: the module will
+          be called psample.
diff --git a/net/psample/Makefile b/net/psample/Makefile
new file mode 100644
index 000000000000..609b0a79c9f3
--- /dev/null
+++ b/net/psample/Makefile
@@ -0,0 +1,5 @@
+#
+# Makefile for the psample netlink channel
+#
+
+obj-$(CONFIG_PSAMPLE) += psample.o
diff --git a/net/psample/psample.c b/net/psample/psample.c
new file mode 100644
index 000000000000..8aa58a918783
--- /dev/null
+++ b/net/psample/psample.c
@@ -0,0 +1,301 @@
+/*
+ * net/psample/psample.c - Netlink channel for packet sampling
+ * Copyright (c) 2017 Yotam Gigi <yotamg@mellanox.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/skbuff.h>
+#include <linux/module.h>
+#include <net/net_namespace.h>
+#include <net/sock.h>
+#include <net/netlink.h>
+#include <net/genetlink.h>
+#include <net/psample.h>
+#include <linux/spinlock.h>
+
+#define PSAMPLE_MAX_PACKET_SIZE 0xffff
+
+static LIST_HEAD(psample_groups_list);
+static DEFINE_SPINLOCK(psample_groups_lock);
+
+/* multicast groups */
+enum psample_nl_multicast_groups {
+        PSAMPLE_NL_MCGRP_CONFIG,
+        PSAMPLE_NL_MCGRP_SAMPLE,
+};
+
+static const struct genl_multicast_group psample_nl_mcgrps[] = {
+        [PSAMPLE_NL_MCGRP_CONFIG] = { .name = PSAMPLE_NL_MCGRP_CONFIG_NAME },
+        [PSAMPLE_NL_MCGRP_SAMPLE] = { .name = PSAMPLE_NL_MCGRP_SAMPLE_NAME },
+};
+
+static struct genl_family psample_nl_family __ro_after_init;
+
+static int psample_group_nl_fill(struct sk_buff *msg,
+                                 struct psample_group *group,
+                                 enum psample_command cmd, u32 portid, u32 seq,
+                                 int flags)
+{
+        void *hdr;
+        int ret;
+
+        hdr = genlmsg_put(msg, portid, seq, &psample_nl_family, flags, cmd);
+        if (!hdr)
+                return -EMSGSIZE;
+
+        ret = nla_put_u32(msg, PSAMPLE_ATTR_SAMPLE_GROUP, group->group_num);
+        if (ret < 0)
+                goto error;
+
+        ret = nla_put_u32(msg, PSAMPLE_ATTR_GROUP_REFCOUNT, group->refcount);
+        if (ret < 0)
+                goto error;
+
+        ret = nla_put_u32(msg, PSAMPLE_ATTR_GROUP_SEQ, group->seq);
+        if (ret < 0)
+                goto error;
+
+        genlmsg_end(msg, hdr);
+        return 0;
+
+error:
+        genlmsg_cancel(msg, hdr);
+        return -EMSGSIZE;
+}
+
+static int psample_nl_cmd_get_group_dumpit(struct sk_buff *msg,
+                                           struct netlink_callback *cb)
+{
+        struct psample_group *group;
+        int start = cb->args[0];
+        int idx = 0;
+        int err;
+
+        spin_lock(&psample_groups_lock);
+        list_for_each_entry(group, &psample_groups_list, list) {
+                if (!net_eq(group->net, sock_net(msg->sk)))
+                        continue;
+                if (idx < start) {
+                        idx++;
+                        continue;
+                }
+                err = psample_group_nl_fill(msg, group, PSAMPLE_CMD_NEW_GROUP,
+                                            NETLINK_CB(cb->skb).portid,
+                                            cb->nlh->nlmsg_seq, NLM_F_MULTI);
+                if (err)
+                        break;
+                idx++;
+        }
+
+        spin_unlock(&psample_groups_lock);
+        cb->args[0] = idx;
+        return msg->len;
+}
+
+static const struct genl_ops psample_nl_ops[] = {
+        {
+                .cmd = PSAMPLE_CMD_GET_GROUP,
+                .dumpit = psample_nl_cmd_get_group_dumpit,
+                /* can be retrieved by unprivileged users */
+        }
+};
+
+static struct genl_family psample_nl_family __ro_after_init = {
+        .name           = PSAMPLE_GENL_NAME,
+        .version        = PSAMPLE_GENL_VERSION,
+        .maxattr        = PSAMPLE_ATTR_MAX,
+        .netnsok        = true,
+        .module         = THIS_MODULE,
+        .mcgrps         = psample_nl_mcgrps,
+        .ops            = psample_nl_ops,
+        .n_ops          = ARRAY_SIZE(psample_nl_ops),
+        .n_mcgrps       = ARRAY_SIZE(psample_nl_mcgrps),
+};
+
+static void psample_group_notify(struct psample_group *group,
+                                 enum psample_command cmd)
+{
+        struct sk_buff *msg;
+        int err;
+
+        msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
+        if (!msg)
+                return;
+
+        err = psample_group_nl_fill(msg, group, cmd, 0, 0, NLM_F_MULTI);
+        if (!err)
+                genlmsg_multicast_netns(&psample_nl_family, group->net, msg, 0,
+                                        PSAMPLE_NL_MCGRP_CONFIG, GFP_ATOMIC);
+        else
+                nlmsg_free(msg);
+}
+
+static struct psample_group *psample_group_create(struct net *net,
+                                                  u32 group_num)
+{
+        struct psample_group *group;
+
+        group = kzalloc(sizeof(*group), GFP_ATOMIC);
+        if (!group)
+                return NULL;
+
+        group->net = net;
+        group->group_num = group_num;
+        list_add_tail(&group->list, &psample_groups_list);
+
+        psample_group_notify(group, PSAMPLE_CMD_NEW_GROUP);
+        return group;
+}
+
+static void psample_group_destroy(struct psample_group *group)
+{
+        psample_group_notify(group, PSAMPLE_CMD_DEL_GROUP);
+        list_del(&group->list);
+        kfree(group);
+}
+
+static struct psample_group *
+psample_group_lookup(struct net *net, u32 group_num)
+{
+        struct psample_group *group;
+
+        list_for_each_entry(group, &psample_groups_list, list)
+                if ((group->group_num == group_num) && (group->net == net))
+                        return group;
+        return NULL;
+}
+
+struct psample_group *psample_group_get(struct net *net, u32 group_num)
+{
+        struct psample_group *group;
+
+        spin_lock(&psample_groups_lock);
+
+        group = psample_group_lookup(net, group_num);
+        if (!group) {
+                group = psample_group_create(net, group_num);
+                if (!group)
+                        goto out;
+        }
+        group->refcount++;
+
+out:
+        spin_unlock(&psample_groups_lock);
+        return group;
+}
+EXPORT_SYMBOL_GPL(psample_group_get);
+
+void psample_group_put(struct psample_group *group)
+{
+        spin_lock(&psample_groups_lock);
+
+        if (--group->refcount == 0)
+                psample_group_destroy(group);
+
+        spin_unlock(&psample_groups_lock);
+}
+EXPORT_SYMBOL_GPL(psample_group_put);
+
+void psample_sample_packet(struct psample_group *group, struct sk_buff *skb,
+                           u32 trunc_size, int in_ifindex, int out_ifindex,
+                           u32 sample_rate)
+{
+        struct sk_buff *nl_skb;
+        int data_len;
+        int meta_len;
+        void *data;
+        int ret;
+
+        meta_len = (in_ifindex ? nla_total_size(sizeof(u16)) : 0) +
+                   (out_ifindex ? nla_total_size(sizeof(u16)) : 0) +
+                   nla_total_size(sizeof(u32)) +        /* sample_rate */
+                   nla_total_size(sizeof(u32)) +        /* orig_size */
+                   nla_total_size(sizeof(u32)) +        /* group_num */
+                   nla_total_size(sizeof(u32));         /* seq */
+
+        data_len = min(skb->len, trunc_size);
+        if (meta_len + nla_total_size(data_len) > PSAMPLE_MAX_PACKET_SIZE)
+                data_len = PSAMPLE_MAX_PACKET_SIZE - meta_len - NLA_HDRLEN
+                            - NLA_ALIGNTO;
+
+        nl_skb = genlmsg_new(meta_len + data_len, GFP_ATOMIC);
+        if (unlikely(!nl_skb))
+                return;
+
+        data = genlmsg_put(nl_skb, 0, 0, &psample_nl_family, 0,
+                           PSAMPLE_CMD_SAMPLE);
+        if (unlikely(!data))
+                goto error;
+
+        if (in_ifindex) {
+                ret = nla_put_u16(nl_skb, PSAMPLE_ATTR_IIFINDEX, in_ifindex);
+                if (unlikely(ret < 0))
+                        goto error;
+        }
+
+        if (out_ifindex) {
+                ret = nla_put_u16(nl_skb, PSAMPLE_ATTR_OIFINDEX, out_ifindex);
+                if (unlikely(ret < 0))
+                        goto error;
+        }
+
+        ret = nla_put_u32(nl_skb, PSAMPLE_ATTR_SAMPLE_RATE, sample_rate);
+        if (unlikely(ret < 0))
+                goto error;
+
+        ret = nla_put_u32(nl_skb, PSAMPLE_ATTR_ORIGSIZE, skb->len);
+        if (unlikely(ret < 0))
+                goto error;
+
+        ret = nla_put_u32(nl_skb, PSAMPLE_ATTR_SAMPLE_GROUP, group->group_num);
+        if (unlikely(ret < 0))
+                goto error;
+
+        ret = nla_put_u32(nl_skb, PSAMPLE_ATTR_GROUP_SEQ, group->seq++);
+        if (unlikely(ret < 0))
+                goto error;
+
+        if (data_len) {
+                int nla_len = nla_total_size(data_len);
+                struct nlattr *nla;
+
+                nla = (struct nlattr *)skb_put(nl_skb, nla_len);
+                nla->nla_type = PSAMPLE_ATTR_DATA;
+                nla->nla_len = nla_attr_size(data_len);
+
+                if (skb_copy_bits(skb, 0, nla_data(nla), data_len))
+                        goto error;
+        }
+
+        genlmsg_end(nl_skb, data);
+        genlmsg_multicast_netns(&psample_nl_family, group->net, nl_skb, 0,
+                                PSAMPLE_NL_MCGRP_SAMPLE, GFP_ATOMIC);
+
+        return;
+error:
+        pr_err_ratelimited("Could not create psample log message\n");
+        nlmsg_free(nl_skb);
+}
+EXPORT_SYMBOL_GPL(psample_sample_packet);
+
+static int __init psample_module_init(void)
+{
+        return genl_register_family(&psample_nl_family);
+}
+
+static void __exit psample_module_exit(void)
+{
+        genl_unregister_family(&psample_nl_family);
+}
+
+module_init(psample_module_init);
+module_exit(psample_module_exit);
+
+MODULE_AUTHOR("Yotam Gigi <yotamg@mellanox.com>");
+MODULE_DESCRIPTION("netlink channel for packet sampling");
+MODULE_LICENSE("GPL v2");