// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* ip_vs_app.c: Application module support for IPVS
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*
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* Authors: Wensong Zhang <wensong@linuxvirtualserver.org>
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*
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* Most code here is taken from ip_masq_app.c in kernel 2.2. The difference
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* is that ip_vs_app module handles the reverse direction (incoming requests
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* and outgoing responses).
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*
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* IP_MASQ_APP application masquerading module
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*
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* Author: Juan Jose Ciarlante, <jjciarla@raiz.uncu.edu.ar>
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*/
|
|
#define KMSG_COMPONENT "IPVS"
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#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
|
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/skbuff.h>
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#include <linux/in.h>
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#include <linux/ip.h>
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#include <linux/netfilter.h>
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#include <linux/slab.h>
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#include <net/net_namespace.h>
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#include <net/protocol.h>
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#include <net/tcp.h>
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#include <linux/stat.h>
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#include <linux/proc_fs.h>
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#include <linux/seq_file.h>
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#include <linux/mutex.h>
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#include <net/ip_vs.h>
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EXPORT_SYMBOL(register_ip_vs_app);
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EXPORT_SYMBOL(unregister_ip_vs_app);
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EXPORT_SYMBOL(register_ip_vs_app_inc);
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static DEFINE_MUTEX(__ip_vs_app_mutex);
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/*
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* Get an ip_vs_app object
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*/
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static inline int ip_vs_app_get(struct ip_vs_app *app)
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{
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return try_module_get(app->module);
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}
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static inline void ip_vs_app_put(struct ip_vs_app *app)
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{
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module_put(app->module);
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}
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static void ip_vs_app_inc_destroy(struct ip_vs_app *inc)
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{
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kfree(inc->timeout_table);
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kfree(inc);
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}
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static void ip_vs_app_inc_rcu_free(struct rcu_head *head)
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{
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struct ip_vs_app *inc = container_of(head, struct ip_vs_app, rcu_head);
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ip_vs_app_inc_destroy(inc);
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}
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/*
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* Allocate/initialize app incarnation and register it in proto apps.
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*/
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static int
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ip_vs_app_inc_new(struct netns_ipvs *ipvs, struct ip_vs_app *app, __u16 proto,
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__u16 port)
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{
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struct ip_vs_protocol *pp;
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struct ip_vs_app *inc;
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int ret;
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if (!(pp = ip_vs_proto_get(proto)))
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return -EPROTONOSUPPORT;
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if (!pp->unregister_app)
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return -EOPNOTSUPP;
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inc = kmemdup(app, sizeof(*inc), GFP_KERNEL);
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if (!inc)
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return -ENOMEM;
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INIT_LIST_HEAD(&inc->p_list);
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INIT_LIST_HEAD(&inc->incs_list);
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inc->app = app;
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inc->port = htons(port);
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atomic_set(&inc->usecnt, 0);
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if (app->timeouts) {
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inc->timeout_table =
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ip_vs_create_timeout_table(app->timeouts,
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app->timeouts_size);
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if (!inc->timeout_table) {
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ret = -ENOMEM;
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goto out;
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}
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}
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ret = pp->register_app(ipvs, inc);
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if (ret)
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goto out;
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list_add(&inc->a_list, &app->incs_list);
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IP_VS_DBG(9, "%s App %s:%u registered\n",
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pp->name, inc->name, ntohs(inc->port));
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return 0;
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out:
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ip_vs_app_inc_destroy(inc);
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return ret;
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}
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/*
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* Release app incarnation
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*/
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static void
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ip_vs_app_inc_release(struct netns_ipvs *ipvs, struct ip_vs_app *inc)
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{
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struct ip_vs_protocol *pp;
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if (!(pp = ip_vs_proto_get(inc->protocol)))
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return;
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if (pp->unregister_app)
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pp->unregister_app(ipvs, inc);
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IP_VS_DBG(9, "%s App %s:%u unregistered\n",
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pp->name, inc->name, ntohs(inc->port));
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list_del(&inc->a_list);
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call_rcu(&inc->rcu_head, ip_vs_app_inc_rcu_free);
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}
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/*
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* Get reference to app inc (only called from softirq)
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*
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*/
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int ip_vs_app_inc_get(struct ip_vs_app *inc)
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{
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int result;
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result = ip_vs_app_get(inc->app);
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if (result)
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atomic_inc(&inc->usecnt);
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return result;
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}
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/*
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* Put the app inc (only called from timer or net softirq)
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*/
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void ip_vs_app_inc_put(struct ip_vs_app *inc)
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{
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atomic_dec(&inc->usecnt);
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ip_vs_app_put(inc->app);
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}
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/*
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* Register an application incarnation in protocol applications
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*/
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int
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register_ip_vs_app_inc(struct netns_ipvs *ipvs, struct ip_vs_app *app, __u16 proto,
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__u16 port)
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{
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int result;
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mutex_lock(&__ip_vs_app_mutex);
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result = ip_vs_app_inc_new(ipvs, app, proto, port);
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mutex_unlock(&__ip_vs_app_mutex);
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return result;
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}
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/* Register application for netns */
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struct ip_vs_app *register_ip_vs_app(struct netns_ipvs *ipvs, struct ip_vs_app *app)
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{
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struct ip_vs_app *a;
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int err = 0;
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mutex_lock(&__ip_vs_app_mutex);
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/* increase the module use count */
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if (!ip_vs_use_count_inc()) {
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err = -ENOENT;
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goto out_unlock;
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}
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list_for_each_entry(a, &ipvs->app_list, a_list) {
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if (!strcmp(app->name, a->name)) {
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err = -EEXIST;
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/* decrease the module use count */
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ip_vs_use_count_dec();
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goto out_unlock;
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}
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}
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a = kmemdup(app, sizeof(*app), GFP_KERNEL);
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if (!a) {
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err = -ENOMEM;
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/* decrease the module use count */
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ip_vs_use_count_dec();
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goto out_unlock;
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}
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INIT_LIST_HEAD(&a->incs_list);
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list_add(&a->a_list, &ipvs->app_list);
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out_unlock:
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mutex_unlock(&__ip_vs_app_mutex);
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return err ? ERR_PTR(err) : a;
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}
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/*
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* ip_vs_app unregistration routine
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* We are sure there are no app incarnations attached to services
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* Caller should use synchronize_rcu() or rcu_barrier()
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*/
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void unregister_ip_vs_app(struct netns_ipvs *ipvs, struct ip_vs_app *app)
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{
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struct ip_vs_app *a, *anxt, *inc, *nxt;
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mutex_lock(&__ip_vs_app_mutex);
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list_for_each_entry_safe(a, anxt, &ipvs->app_list, a_list) {
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if (app && strcmp(app->name, a->name))
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continue;
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list_for_each_entry_safe(inc, nxt, &a->incs_list, a_list) {
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ip_vs_app_inc_release(ipvs, inc);
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}
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list_del(&a->a_list);
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kfree(a);
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/* decrease the module use count */
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ip_vs_use_count_dec();
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}
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mutex_unlock(&__ip_vs_app_mutex);
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}
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/*
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* Bind ip_vs_conn to its ip_vs_app (called by cp constructor)
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*/
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int ip_vs_bind_app(struct ip_vs_conn *cp,
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struct ip_vs_protocol *pp)
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{
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return pp->app_conn_bind(cp);
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}
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/*
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* Unbind cp from application incarnation (called by cp destructor)
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*/
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void ip_vs_unbind_app(struct ip_vs_conn *cp)
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{
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struct ip_vs_app *inc = cp->app;
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if (!inc)
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return;
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if (inc->unbind_conn)
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inc->unbind_conn(inc, cp);
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if (inc->done_conn)
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inc->done_conn(inc, cp);
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ip_vs_app_inc_put(inc);
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cp->app = NULL;
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}
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/*
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* Fixes th->seq based on ip_vs_seq info.
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*/
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static inline void vs_fix_seq(const struct ip_vs_seq *vseq, struct tcphdr *th)
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{
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__u32 seq = ntohl(th->seq);
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/*
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* Adjust seq with delta-offset for all packets after
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* the most recent resized pkt seq and with previous_delta offset
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* for all packets before most recent resized pkt seq.
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*/
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if (vseq->delta || vseq->previous_delta) {
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if(after(seq, vseq->init_seq)) {
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th->seq = htonl(seq + vseq->delta);
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IP_VS_DBG(9, "%s(): added delta (%d) to seq\n",
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__func__, vseq->delta);
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} else {
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th->seq = htonl(seq + vseq->previous_delta);
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IP_VS_DBG(9, "%s(): added previous_delta (%d) to seq\n",
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__func__, vseq->previous_delta);
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}
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}
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}
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/*
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* Fixes th->ack_seq based on ip_vs_seq info.
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*/
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static inline void
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vs_fix_ack_seq(const struct ip_vs_seq *vseq, struct tcphdr *th)
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{
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__u32 ack_seq = ntohl(th->ack_seq);
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/*
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* Adjust ack_seq with delta-offset for
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* the packets AFTER most recent resized pkt has caused a shift
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* for packets before most recent resized pkt, use previous_delta
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*/
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if (vseq->delta || vseq->previous_delta) {
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/* since ack_seq is the number of octet that is expected
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to receive next, so compare it with init_seq+delta */
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if(after(ack_seq, vseq->init_seq+vseq->delta)) {
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th->ack_seq = htonl(ack_seq - vseq->delta);
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IP_VS_DBG(9, "%s(): subtracted delta "
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"(%d) from ack_seq\n", __func__, vseq->delta);
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} else {
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th->ack_seq = htonl(ack_seq - vseq->previous_delta);
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IP_VS_DBG(9, "%s(): subtracted "
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"previous_delta (%d) from ack_seq\n",
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__func__, vseq->previous_delta);
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}
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}
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}
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/*
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* Updates ip_vs_seq if pkt has been resized
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* Assumes already checked proto==IPPROTO_TCP and diff!=0.
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*/
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static inline void vs_seq_update(struct ip_vs_conn *cp, struct ip_vs_seq *vseq,
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unsigned int flag, __u32 seq, int diff)
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{
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/* spinlock is to keep updating cp->flags atomic */
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spin_lock_bh(&cp->lock);
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if (!(cp->flags & flag) || after(seq, vseq->init_seq)) {
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vseq->previous_delta = vseq->delta;
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vseq->delta += diff;
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vseq->init_seq = seq;
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cp->flags |= flag;
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}
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spin_unlock_bh(&cp->lock);
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}
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static inline int app_tcp_pkt_out(struct ip_vs_conn *cp, struct sk_buff *skb,
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struct ip_vs_app *app,
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struct ip_vs_iphdr *ipvsh)
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{
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int diff;
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const unsigned int tcp_offset = ip_hdrlen(skb);
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struct tcphdr *th;
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__u32 seq;
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if (skb_ensure_writable(skb, tcp_offset + sizeof(*th)))
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return 0;
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th = (struct tcphdr *)(skb_network_header(skb) + tcp_offset);
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/*
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* Remember seq number in case this pkt gets resized
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*/
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seq = ntohl(th->seq);
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/*
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* Fix seq stuff if flagged as so.
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*/
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if (cp->flags & IP_VS_CONN_F_OUT_SEQ)
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vs_fix_seq(&cp->out_seq, th);
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if (cp->flags & IP_VS_CONN_F_IN_SEQ)
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vs_fix_ack_seq(&cp->in_seq, th);
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/*
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* Call private output hook function
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*/
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if (app->pkt_out == NULL)
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return 1;
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if (!app->pkt_out(app, cp, skb, &diff, ipvsh))
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return 0;
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/*
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* Update ip_vs seq stuff if len has changed.
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*/
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if (diff != 0)
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vs_seq_update(cp, &cp->out_seq,
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IP_VS_CONN_F_OUT_SEQ, seq, diff);
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return 1;
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}
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/*
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* Output pkt hook. Will call bound ip_vs_app specific function
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* called by ipvs packet handler, assumes previously checked cp!=NULL
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* returns false if it can't handle packet (oom)
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*/
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int ip_vs_app_pkt_out(struct ip_vs_conn *cp, struct sk_buff *skb,
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struct ip_vs_iphdr *ipvsh)
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{
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struct ip_vs_app *app;
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/*
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* check if application module is bound to
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* this ip_vs_conn.
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*/
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if ((app = cp->app) == NULL)
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return 1;
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/* TCP is complicated */
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if (cp->protocol == IPPROTO_TCP)
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return app_tcp_pkt_out(cp, skb, app, ipvsh);
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/*
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* Call private output hook function
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*/
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if (app->pkt_out == NULL)
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return 1;
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return app->pkt_out(app, cp, skb, NULL, ipvsh);
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}
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static inline int app_tcp_pkt_in(struct ip_vs_conn *cp, struct sk_buff *skb,
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struct ip_vs_app *app,
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struct ip_vs_iphdr *ipvsh)
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{
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int diff;
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const unsigned int tcp_offset = ip_hdrlen(skb);
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struct tcphdr *th;
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__u32 seq;
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if (skb_ensure_writable(skb, tcp_offset + sizeof(*th)))
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return 0;
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th = (struct tcphdr *)(skb_network_header(skb) + tcp_offset);
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/*
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* Remember seq number in case this pkt gets resized
|
*/
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seq = ntohl(th->seq);
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/*
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* Fix seq stuff if flagged as so.
|
*/
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if (cp->flags & IP_VS_CONN_F_IN_SEQ)
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vs_fix_seq(&cp->in_seq, th);
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if (cp->flags & IP_VS_CONN_F_OUT_SEQ)
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vs_fix_ack_seq(&cp->out_seq, th);
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/*
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* Call private input hook function
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*/
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if (app->pkt_in == NULL)
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return 1;
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if (!app->pkt_in(app, cp, skb, &diff, ipvsh))
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return 0;
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/*
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* Update ip_vs seq stuff if len has changed.
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*/
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if (diff != 0)
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vs_seq_update(cp, &cp->in_seq,
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IP_VS_CONN_F_IN_SEQ, seq, diff);
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return 1;
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}
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/*
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* Input pkt hook. Will call bound ip_vs_app specific function
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* called by ipvs packet handler, assumes previously checked cp!=NULL.
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* returns false if can't handle packet (oom).
|
*/
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int ip_vs_app_pkt_in(struct ip_vs_conn *cp, struct sk_buff *skb,
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struct ip_vs_iphdr *ipvsh)
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{
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struct ip_vs_app *app;
|
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/*
|
* check if application module is bound to
|
* this ip_vs_conn.
|
*/
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if ((app = cp->app) == NULL)
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return 1;
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/* TCP is complicated */
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if (cp->protocol == IPPROTO_TCP)
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return app_tcp_pkt_in(cp, skb, app, ipvsh);
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/*
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* Call private input hook function
|
*/
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if (app->pkt_in == NULL)
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return 1;
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return app->pkt_in(app, cp, skb, NULL, ipvsh);
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}
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|
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#ifdef CONFIG_PROC_FS
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/*
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* /proc/net/ip_vs_app entry function
|
*/
|
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static struct ip_vs_app *ip_vs_app_idx(struct netns_ipvs *ipvs, loff_t pos)
|
{
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struct ip_vs_app *app, *inc;
|
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list_for_each_entry(app, &ipvs->app_list, a_list) {
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list_for_each_entry(inc, &app->incs_list, a_list) {
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if (pos-- == 0)
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return inc;
|
}
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}
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return NULL;
|
|
}
|
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static void *ip_vs_app_seq_start(struct seq_file *seq, loff_t *pos)
|
{
|
struct net *net = seq_file_net(seq);
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struct netns_ipvs *ipvs = net_ipvs(net);
|
|
mutex_lock(&__ip_vs_app_mutex);
|
|
return *pos ? ip_vs_app_idx(ipvs, *pos - 1) : SEQ_START_TOKEN;
|
}
|
|
static void *ip_vs_app_seq_next(struct seq_file *seq, void *v, loff_t *pos)
|
{
|
struct ip_vs_app *inc, *app;
|
struct list_head *e;
|
struct net *net = seq_file_net(seq);
|
struct netns_ipvs *ipvs = net_ipvs(net);
|
|
++*pos;
|
if (v == SEQ_START_TOKEN)
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return ip_vs_app_idx(ipvs, 0);
|
|
inc = v;
|
app = inc->app;
|
|
if ((e = inc->a_list.next) != &app->incs_list)
|
return list_entry(e, struct ip_vs_app, a_list);
|
|
/* go on to next application */
|
for (e = app->a_list.next; e != &ipvs->app_list; e = e->next) {
|
app = list_entry(e, struct ip_vs_app, a_list);
|
list_for_each_entry(inc, &app->incs_list, a_list) {
|
return inc;
|
}
|
}
|
return NULL;
|
}
|
|
static void ip_vs_app_seq_stop(struct seq_file *seq, void *v)
|
{
|
mutex_unlock(&__ip_vs_app_mutex);
|
}
|
|
static int ip_vs_app_seq_show(struct seq_file *seq, void *v)
|
{
|
if (v == SEQ_START_TOKEN)
|
seq_puts(seq, "prot port usecnt name\n");
|
else {
|
const struct ip_vs_app *inc = v;
|
|
seq_printf(seq, "%-3s %-7u %-6d %-17s\n",
|
ip_vs_proto_name(inc->protocol),
|
ntohs(inc->port),
|
atomic_read(&inc->usecnt),
|
inc->name);
|
}
|
return 0;
|
}
|
|
static const struct seq_operations ip_vs_app_seq_ops = {
|
.start = ip_vs_app_seq_start,
|
.next = ip_vs_app_seq_next,
|
.stop = ip_vs_app_seq_stop,
|
.show = ip_vs_app_seq_show,
|
};
|
#endif
|
|
int __net_init ip_vs_app_net_init(struct netns_ipvs *ipvs)
|
{
|
INIT_LIST_HEAD(&ipvs->app_list);
|
#ifdef CONFIG_PROC_FS
|
if (!proc_create_net("ip_vs_app", 0, ipvs->net->proc_net,
|
&ip_vs_app_seq_ops,
|
sizeof(struct seq_net_private)))
|
return -ENOMEM;
|
#endif
|
return 0;
|
}
|
|
void __net_exit ip_vs_app_net_cleanup(struct netns_ipvs *ipvs)
|
{
|
unregister_ip_vs_app(ipvs, NULL /* all */);
|
#ifdef CONFIG_PROC_FS
|
remove_proc_entry("ip_vs_app", ipvs->net->proc_net);
|
#endif
|
}
|
