| /* |
| * ip_vs_app.c: Application module support for IPVS |
| * |
| * Authors: Wensong Zhang <wensong@linuxvirtualserver.org> |
| * |
| * This program is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU General Public License |
| * as published by the Free Software Foundation; either version |
| * 2 of the License, or (at your option) any later version. |
| * |
| * Most code here is taken from ip_masq_app.c in kernel 2.2. The difference |
| * is that ip_vs_app module handles the reverse direction (incoming requests |
| * and outgoing responses). |
| * |
| * IP_MASQ_APP application masquerading module |
| * |
| * Author: Juan Jose Ciarlante, <jjciarla@raiz.uncu.edu.ar> |
| * |
| */ |
| |
| #define KMSG_COMPONENT "IPVS" |
| #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt |
| |
| #include <linux/module.h> |
| #include <linux/kernel.h> |
| #include <linux/skbuff.h> |
| #include <linux/in.h> |
| #include <linux/ip.h> |
| #include <linux/netfilter.h> |
| #include <linux/slab.h> |
| #include <net/net_namespace.h> |
| #include <net/protocol.h> |
| #include <net/tcp.h> |
| #include <asm/system.h> |
| #include <linux/stat.h> |
| #include <linux/proc_fs.h> |
| #include <linux/seq_file.h> |
| #include <linux/mutex.h> |
| |
| #include <net/ip_vs.h> |
| |
| EXPORT_SYMBOL(register_ip_vs_app); |
| EXPORT_SYMBOL(unregister_ip_vs_app); |
| EXPORT_SYMBOL(register_ip_vs_app_inc); |
| |
| /* ipvs application list head */ |
| static LIST_HEAD(ip_vs_app_list); |
| static DEFINE_MUTEX(__ip_vs_app_mutex); |
| |
| |
| /* |
| * Get an ip_vs_app object |
| */ |
| static inline int ip_vs_app_get(struct ip_vs_app *app) |
| { |
| return try_module_get(app->module); |
| } |
| |
| |
| static inline void ip_vs_app_put(struct ip_vs_app *app) |
| { |
| module_put(app->module); |
| } |
| |
| |
| /* |
| * Allocate/initialize app incarnation and register it in proto apps. |
| */ |
| static int |
| ip_vs_app_inc_new(struct ip_vs_app *app, __u16 proto, __u16 port) |
| { |
| struct ip_vs_protocol *pp; |
| struct ip_vs_app *inc; |
| int ret; |
| |
| if (!(pp = ip_vs_proto_get(proto))) |
| return -EPROTONOSUPPORT; |
| |
| if (!pp->unregister_app) |
| return -EOPNOTSUPP; |
| |
| inc = kmemdup(app, sizeof(*inc), GFP_KERNEL); |
| if (!inc) |
| return -ENOMEM; |
| INIT_LIST_HEAD(&inc->p_list); |
| INIT_LIST_HEAD(&inc->incs_list); |
| inc->app = app; |
| inc->port = htons(port); |
| atomic_set(&inc->usecnt, 0); |
| |
| if (app->timeouts) { |
| inc->timeout_table = |
| ip_vs_create_timeout_table(app->timeouts, |
| app->timeouts_size); |
| if (!inc->timeout_table) { |
| ret = -ENOMEM; |
| goto out; |
| } |
| } |
| |
| ret = pp->register_app(inc); |
| if (ret) |
| goto out; |
| |
| list_add(&inc->a_list, &app->incs_list); |
| IP_VS_DBG(9, "%s App %s:%u registered\n", |
| pp->name, inc->name, ntohs(inc->port)); |
| |
| return 0; |
| |
| out: |
| kfree(inc->timeout_table); |
| kfree(inc); |
| return ret; |
| } |
| |
| |
| /* |
| * Release app incarnation |
| */ |
| static void |
| ip_vs_app_inc_release(struct ip_vs_app *inc) |
| { |
| struct ip_vs_protocol *pp; |
| |
| if (!(pp = ip_vs_proto_get(inc->protocol))) |
| return; |
| |
| if (pp->unregister_app) |
| pp->unregister_app(inc); |
| |
| IP_VS_DBG(9, "%s App %s:%u unregistered\n", |
| pp->name, inc->name, ntohs(inc->port)); |
| |
| list_del(&inc->a_list); |
| |
| kfree(inc->timeout_table); |
| kfree(inc); |
| } |
| |
| |
| /* |
| * Get reference to app inc (only called from softirq) |
| * |
| */ |
| int ip_vs_app_inc_get(struct ip_vs_app *inc) |
| { |
| int result; |
| |
| atomic_inc(&inc->usecnt); |
| if (unlikely((result = ip_vs_app_get(inc->app)) != 1)) |
| atomic_dec(&inc->usecnt); |
| return result; |
| } |
| |
| |
| /* |
| * Put the app inc (only called from timer or net softirq) |
| */ |
| void ip_vs_app_inc_put(struct ip_vs_app *inc) |
| { |
| ip_vs_app_put(inc->app); |
| atomic_dec(&inc->usecnt); |
| } |
| |
| |
| /* |
| * Register an application incarnation in protocol applications |
| */ |
| int |
| register_ip_vs_app_inc(struct ip_vs_app *app, __u16 proto, __u16 port) |
| { |
| int result; |
| |
| mutex_lock(&__ip_vs_app_mutex); |
| |
| result = ip_vs_app_inc_new(app, proto, port); |
| |
| mutex_unlock(&__ip_vs_app_mutex); |
| |
| return result; |
| } |
| |
| |
| /* |
| * ip_vs_app registration routine |
| */ |
| int register_ip_vs_app(struct ip_vs_app *app) |
| { |
| /* increase the module use count */ |
| ip_vs_use_count_inc(); |
| |
| mutex_lock(&__ip_vs_app_mutex); |
| |
| list_add(&app->a_list, &ip_vs_app_list); |
| |
| mutex_unlock(&__ip_vs_app_mutex); |
| |
| return 0; |
| } |
| |
| |
| /* |
| * ip_vs_app unregistration routine |
| * We are sure there are no app incarnations attached to services |
| */ |
| void unregister_ip_vs_app(struct ip_vs_app *app) |
| { |
| struct ip_vs_app *inc, *nxt; |
| |
| mutex_lock(&__ip_vs_app_mutex); |
| |
| list_for_each_entry_safe(inc, nxt, &app->incs_list, a_list) { |
| ip_vs_app_inc_release(inc); |
| } |
| |
| list_del(&app->a_list); |
| |
| mutex_unlock(&__ip_vs_app_mutex); |
| |
| /* decrease the module use count */ |
| ip_vs_use_count_dec(); |
| } |
| |
| |
| /* |
| * Bind ip_vs_conn to its ip_vs_app (called by cp constructor) |
| */ |
| int ip_vs_bind_app(struct ip_vs_conn *cp, struct ip_vs_protocol *pp) |
| { |
| return pp->app_conn_bind(cp); |
| } |
| |
| |
| /* |
| * Unbind cp from application incarnation (called by cp destructor) |
| */ |
| void ip_vs_unbind_app(struct ip_vs_conn *cp) |
| { |
| struct ip_vs_app *inc = cp->app; |
| |
| if (!inc) |
| return; |
| |
| if (inc->unbind_conn) |
| inc->unbind_conn(inc, cp); |
| if (inc->done_conn) |
| inc->done_conn(inc, cp); |
| ip_vs_app_inc_put(inc); |
| cp->app = NULL; |
| } |
| |
| |
| /* |
| * Fixes th->seq based on ip_vs_seq info. |
| */ |
| static inline void vs_fix_seq(const struct ip_vs_seq *vseq, struct tcphdr *th) |
| { |
| __u32 seq = ntohl(th->seq); |
| |
| /* |
| * Adjust seq with delta-offset for all packets after |
| * the most recent resized pkt seq and with previous_delta offset |
| * for all packets before most recent resized pkt seq. |
| */ |
| if (vseq->delta || vseq->previous_delta) { |
| if(after(seq, vseq->init_seq)) { |
| th->seq = htonl(seq + vseq->delta); |
| IP_VS_DBG(9, "%s(): added delta (%d) to seq\n", |
| __func__, vseq->delta); |
| } else { |
| th->seq = htonl(seq + vseq->previous_delta); |
| IP_VS_DBG(9, "%s(): added previous_delta (%d) to seq\n", |
| __func__, vseq->previous_delta); |
| } |
| } |
| } |
| |
| |
| /* |
| * Fixes th->ack_seq based on ip_vs_seq info. |
| */ |
| static inline void |
| vs_fix_ack_seq(const struct ip_vs_seq *vseq, struct tcphdr *th) |
| { |
| __u32 ack_seq = ntohl(th->ack_seq); |
| |
| /* |
| * Adjust ack_seq with delta-offset for |
| * the packets AFTER most recent resized pkt has caused a shift |
| * for packets before most recent resized pkt, use previous_delta |
| */ |
| if (vseq->delta || vseq->previous_delta) { |
| /* since ack_seq is the number of octet that is expected |
| to receive next, so compare it with init_seq+delta */ |
| if(after(ack_seq, vseq->init_seq+vseq->delta)) { |
| th->ack_seq = htonl(ack_seq - vseq->delta); |
| IP_VS_DBG(9, "%s(): subtracted delta " |
| "(%d) from ack_seq\n", __func__, vseq->delta); |
| |
| } else { |
| th->ack_seq = htonl(ack_seq - vseq->previous_delta); |
| IP_VS_DBG(9, "%s(): subtracted " |
| "previous_delta (%d) from ack_seq\n", |
| __func__, vseq->previous_delta); |
| } |
| } |
| } |
| |
| |
| /* |
| * Updates ip_vs_seq if pkt has been resized |
| * Assumes already checked proto==IPPROTO_TCP and diff!=0. |
| */ |
| static inline void vs_seq_update(struct ip_vs_conn *cp, struct ip_vs_seq *vseq, |
| unsigned flag, __u32 seq, int diff) |
| { |
| /* spinlock is to keep updating cp->flags atomic */ |
| spin_lock(&cp->lock); |
| if (!(cp->flags & flag) || after(seq, vseq->init_seq)) { |
| vseq->previous_delta = vseq->delta; |
| vseq->delta += diff; |
| vseq->init_seq = seq; |
| cp->flags |= flag; |
| } |
| spin_unlock(&cp->lock); |
| } |
| |
| static inline int app_tcp_pkt_out(struct ip_vs_conn *cp, struct sk_buff *skb, |
| struct ip_vs_app *app) |
| { |
| int diff; |
| const unsigned int tcp_offset = ip_hdrlen(skb); |
| struct tcphdr *th; |
| __u32 seq; |
| |
| if (!skb_make_writable(skb, tcp_offset + sizeof(*th))) |
| return 0; |
| |
| th = (struct tcphdr *)(skb_network_header(skb) + tcp_offset); |
| |
| /* |
| * Remember seq number in case this pkt gets resized |
| */ |
| seq = ntohl(th->seq); |
| |
| /* |
| * Fix seq stuff if flagged as so. |
| */ |
| if (cp->flags & IP_VS_CONN_F_OUT_SEQ) |
| vs_fix_seq(&cp->out_seq, th); |
| if (cp->flags & IP_VS_CONN_F_IN_SEQ) |
| vs_fix_ack_seq(&cp->in_seq, th); |
| |
| /* |
| * Call private output hook function |
| */ |
| if (app->pkt_out == NULL) |
| return 1; |
| |
| if (!app->pkt_out(app, cp, skb, &diff)) |
| return 0; |
| |
| /* |
| * Update ip_vs seq stuff if len has changed. |
| */ |
| if (diff != 0) |
| vs_seq_update(cp, &cp->out_seq, |
| IP_VS_CONN_F_OUT_SEQ, seq, diff); |
| |
| return 1; |
| } |
| |
| /* |
| * Output pkt hook. Will call bound ip_vs_app specific function |
| * called by ipvs packet handler, assumes previously checked cp!=NULL |
| * returns false if it can't handle packet (oom) |
| */ |
| int ip_vs_app_pkt_out(struct ip_vs_conn *cp, struct sk_buff *skb) |
| { |
| struct ip_vs_app *app; |
| |
| /* |
| * check if application module is bound to |
| * this ip_vs_conn. |
| */ |
| if ((app = cp->app) == NULL) |
| return 1; |
| |
| /* TCP is complicated */ |
| if (cp->protocol == IPPROTO_TCP) |
| return app_tcp_pkt_out(cp, skb, app); |
| |
| /* |
| * Call private output hook function |
| */ |
| if (app->pkt_out == NULL) |
| return 1; |
| |
| return app->pkt_out(app, cp, skb, NULL); |
| } |
| |
| |
| static inline int app_tcp_pkt_in(struct ip_vs_conn *cp, struct sk_buff *skb, |
| struct ip_vs_app *app) |
| { |
| int diff; |
| const unsigned int tcp_offset = ip_hdrlen(skb); |
| struct tcphdr *th; |
| __u32 seq; |
| |
| if (!skb_make_writable(skb, tcp_offset + sizeof(*th))) |
| return 0; |
| |
| th = (struct tcphdr *)(skb_network_header(skb) + tcp_offset); |
| |
| /* |
| * Remember seq number in case this pkt gets resized |
| */ |
| seq = ntohl(th->seq); |
| |
| /* |
| * Fix seq stuff if flagged as so. |
| */ |
| if (cp->flags & IP_VS_CONN_F_IN_SEQ) |
| vs_fix_seq(&cp->in_seq, th); |
| if (cp->flags & IP_VS_CONN_F_OUT_SEQ) |
| vs_fix_ack_seq(&cp->out_seq, th); |
| |
| /* |
| * Call private input hook function |
| */ |
| if (app->pkt_in == NULL) |
| return 1; |
| |
| if (!app->pkt_in(app, cp, skb, &diff)) |
| return 0; |
| |
| /* |
| * Update ip_vs seq stuff if len has changed. |
| */ |
| if (diff != 0) |
| vs_seq_update(cp, &cp->in_seq, |
| IP_VS_CONN_F_IN_SEQ, seq, diff); |
| |
| return 1; |
| } |
| |
| /* |
| * Input pkt hook. Will call bound ip_vs_app specific function |
| * called by ipvs packet handler, assumes previously checked cp!=NULL. |
| * returns false if can't handle packet (oom). |
| */ |
| int ip_vs_app_pkt_in(struct ip_vs_conn *cp, struct sk_buff *skb) |
| { |
| struct ip_vs_app *app; |
| |
| /* |
| * check if application module is bound to |
| * this ip_vs_conn. |
| */ |
| if ((app = cp->app) == NULL) |
| return 1; |
| |
| /* TCP is complicated */ |
| if (cp->protocol == IPPROTO_TCP) |
| return app_tcp_pkt_in(cp, skb, app); |
| |
| /* |
| * Call private input hook function |
| */ |
| if (app->pkt_in == NULL) |
| return 1; |
| |
| return app->pkt_in(app, cp, skb, NULL); |
| } |
| |
| |
| #ifdef CONFIG_PROC_FS |
| /* |
| * /proc/net/ip_vs_app entry function |
| */ |
| |
| static struct ip_vs_app *ip_vs_app_idx(loff_t pos) |
| { |
| struct ip_vs_app *app, *inc; |
| |
| list_for_each_entry(app, &ip_vs_app_list, a_list) { |
| list_for_each_entry(inc, &app->incs_list, a_list) { |
| if (pos-- == 0) |
| return inc; |
| } |
| } |
| return NULL; |
| |
| } |
| |
| static void *ip_vs_app_seq_start(struct seq_file *seq, loff_t *pos) |
| { |
| mutex_lock(&__ip_vs_app_mutex); |
| |
| return *pos ? ip_vs_app_idx(*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; |
| |
| ++*pos; |
| if (v == SEQ_START_TOKEN) |
| return ip_vs_app_idx(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 != &ip_vs_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, |
| }; |
| |
| static int ip_vs_app_open(struct inode *inode, struct file *file) |
| { |
| return seq_open(file, &ip_vs_app_seq_ops); |
| } |
| |
| static const struct file_operations ip_vs_app_fops = { |
| .owner = THIS_MODULE, |
| .open = ip_vs_app_open, |
| .read = seq_read, |
| .llseek = seq_lseek, |
| .release = seq_release, |
| }; |
| #endif |
| |
| int __init ip_vs_app_init(void) |
| { |
| /* we will replace it with proc_net_ipvs_create() soon */ |
| proc_net_fops_create(&init_net, "ip_vs_app", 0, &ip_vs_app_fops); |
| return 0; |
| } |
| |
| |
| void ip_vs_app_cleanup(void) |
| { |
| proc_net_remove(&init_net, "ip_vs_app"); |
| } |