From a5f7a5bb3b7f28ba7e4fa246775b29a0e5537255 Mon Sep 17 00:00:00 2001 From: Jinke Han Date: Tue, 8 Sep 2026 15:37:42 +0800 Subject: x86/kprobes: Fix crash when probing CS CALL instructions When using eBPF to probe CS CALL instructions within a function, a crash can be triggered. The eBPF tool probes offset 257 of the __hrtimer_run_queues() function: <__hrtimer_run_queues+249>: nopl 0x0(%rax,%rax,1) <__hrtimer_run_queues+254>: mov %r14,%rdi <__hrtimer_run_queues+257>: cs call <__x86_indirect_thunk_r12> <__hrtimer_run_queues+263>: mov %eax,%r12d <__hrtimer_run_queues+266>: xchg %ax,%ax <__hrtimer_run_queues+268>: mov %r13,%rdi Which triggers this crash: BUG: unable to handle page fault for address: 00000000000f41c9 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 0 P4D 0 Oops: 0002 [#1] SMP NOPTI CPU: 1 PID: 0 Comm: swapper/1 Kdump: loaded Tainted: P RIP: 0010:__hrtimer_run_queues+0x106/0x230 Note that __hrtimer_run_queues+0x106 is __hrtimer_run_queues+262, which is at the 6th byte of the above CS CALL instruction. Since the CS CALL instruction occupies 6 bytes, the exception occurred in the middle of that call instruction. The root cause is that when using eBPF tools to probe in the middle of a function, a kprobe with INT3 is used as the underlying implementation. During single-step emulation of the original CALL instruction, int3_emulate_call() assumes that the probed CALL instruction is 5 bytes long. However, the actual CS-prefixed CALL instruction occupies 6 bytes, so it constructs an incorrect exception return address. When the CPU returns from the kprobe handler, the next instruction to be executed is at the address of the last byte of that CS CALL instruction. Coincidentally, starting from that address, the CPU fetches and decodes a completely different instruction, which ultimately triggers a kernel crash. Fix the issue by using the actual instruction length obtained from the instruction decoder when constructing the exception return address, rather than relying on the hardcoded CALL_INSN_SIZE macro. [ mingo: Refined the changelog ] Fixes: 6256e668b7af ("x86/kprobes: Use int3 instead of debug trap for single-step") Suggested-by: Masami Hiramatsu (Google) Signed-off-by: Jinke Han Signed-off-by: Ingo Molnar Reviewed-by: Masami Hiramatsu (Google) Acked-by: Yafang Shao Acked-by: Borislav Petkov Cc: Peter Zijlstra Link: https://patch.msgid.link/20260908073742.GA10517@didi-ThinkCentre-M920t-N000 --- net/802/garp.c | 653 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 653 insertions(+) create mode 100644 net/802/garp.c (limited to 'net/802/garp.c') diff --git a/net/802/garp.c b/net/802/garp.c new file mode 100644 index 000000000..56b934ec1 --- /dev/null +++ b/net/802/garp.c @@ -0,0 +1,653 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * IEEE 802.1D Generic Attribute Registration Protocol (GARP) + * + * Copyright (c) 2008 Patrick McHardy + */ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +static unsigned int garp_join_time __read_mostly = 200; +module_param(garp_join_time, uint, 0644); +MODULE_PARM_DESC(garp_join_time, "Join time in ms (default 200ms)"); +MODULE_DESCRIPTION("IEEE 802.1D Generic Attribute Registration Protocol (GARP)"); +MODULE_LICENSE("GPL"); + +static const struct garp_state_trans { + u8 state; + u8 action; +} garp_applicant_state_table[GARP_APPLICANT_MAX + 1][GARP_EVENT_MAX + 1] = { + [GARP_APPLICANT_VA] = { + [GARP_EVENT_TRANSMIT_PDU] = { .state = GARP_APPLICANT_AA, + .action = GARP_ACTION_S_JOIN_IN }, + [GARP_EVENT_R_JOIN_IN] = { .state = GARP_APPLICANT_AA }, + [GARP_EVENT_R_JOIN_EMPTY] = { .state = GARP_APPLICANT_VA }, + [GARP_EVENT_R_EMPTY] = { .state = GARP_APPLICANT_VA }, + [GARP_EVENT_R_LEAVE_IN] = { .state = GARP_APPLICANT_VA }, + [GARP_EVENT_R_LEAVE_EMPTY] = { .state = GARP_APPLICANT_VP }, + [GARP_EVENT_REQ_JOIN] = { .state = GARP_APPLICANT_INVALID }, + [GARP_EVENT_REQ_LEAVE] = { .state = GARP_APPLICANT_LA }, + }, + [GARP_APPLICANT_AA] = { + [GARP_EVENT_TRANSMIT_PDU] = { .state = GARP_APPLICANT_QA, + .action = GARP_ACTION_S_JOIN_IN }, + [GARP_EVENT_R_JOIN_IN] = { .state = GARP_APPLICANT_QA }, + [GARP_EVENT_R_JOIN_EMPTY] = { .state = GARP_APPLICANT_VA }, + [GARP_EVENT_R_EMPTY] = { .state = GARP_APPLICANT_VA }, + [GARP_EVENT_R_LEAVE_IN] = { .state = GARP_APPLICANT_VA }, + [GARP_EVENT_R_LEAVE_EMPTY] = { .state = GARP_APPLICANT_VP }, + [GARP_EVENT_REQ_JOIN] = { .state = GARP_APPLICANT_INVALID }, + [GARP_EVENT_REQ_LEAVE] = { .state = GARP_APPLICANT_LA }, + }, + [GARP_APPLICANT_QA] = { + [GARP_EVENT_TRANSMIT_PDU] = { .state = GARP_APPLICANT_INVALID }, + [GARP_EVENT_R_JOIN_IN] = { .state = GARP_APPLICANT_QA }, + [GARP_EVENT_R_JOIN_EMPTY] = { .state = GARP_APPLICANT_VA }, + [GARP_EVENT_R_EMPTY] = { .state = GARP_APPLICANT_VA }, + [GARP_EVENT_R_LEAVE_IN] = { .state = GARP_APPLICANT_VP }, + [GARP_EVENT_R_LEAVE_EMPTY] = { .state = GARP_APPLICANT_VP }, + [GARP_EVENT_REQ_JOIN] = { .state = GARP_APPLICANT_INVALID }, + [GARP_EVENT_REQ_LEAVE] = { .state = GARP_APPLICANT_LA }, + }, + [GARP_APPLICANT_LA] = { + [GARP_EVENT_TRANSMIT_PDU] = { .state = GARP_APPLICANT_VO, + .action = GARP_ACTION_S_LEAVE_EMPTY }, + [GARP_EVENT_R_JOIN_IN] = { .state = GARP_APPLICANT_LA }, + [GARP_EVENT_R_JOIN_EMPTY] = { .state = GARP_APPLICANT_VO }, + [GARP_EVENT_R_EMPTY] = { .state = GARP_APPLICANT_LA }, + [GARP_EVENT_R_LEAVE_IN] = { .state = GARP_APPLICANT_LA }, + [GARP_EVENT_R_LEAVE_EMPTY] = { .state = GARP_APPLICANT_VO }, + [GARP_EVENT_REQ_JOIN] = { .state = GARP_APPLICANT_VA }, + [GARP_EVENT_REQ_LEAVE] = { .state = GARP_APPLICANT_INVALID }, + }, + [GARP_APPLICANT_VP] = { + [GARP_EVENT_TRANSMIT_PDU] = { .state = GARP_APPLICANT_AA, + .action = GARP_ACTION_S_JOIN_IN }, + [GARP_EVENT_R_JOIN_IN] = { .state = GARP_APPLICANT_AP }, + [GARP_EVENT_R_JOIN_EMPTY] = { .state = GARP_APPLICANT_VP }, + [GARP_EVENT_R_EMPTY] = { .state = GARP_APPLICANT_VP }, + [GARP_EVENT_R_LEAVE_IN] = { .state = GARP_APPLICANT_VP }, + [GARP_EVENT_R_LEAVE_EMPTY] = { .state = GARP_APPLICANT_VP }, + [GARP_EVENT_REQ_JOIN] = { .state = GARP_APPLICANT_INVALID }, + [GARP_EVENT_REQ_LEAVE] = { .state = GARP_APPLICANT_VO }, + }, + [GARP_APPLICANT_AP] = { + [GARP_EVENT_TRANSMIT_PDU] = { .state = GARP_APPLICANT_QA, + .action = GARP_ACTION_S_JOIN_IN }, + [GARP_EVENT_R_JOIN_IN] = { .state = GARP_APPLICANT_QP }, + [GARP_EVENT_R_JOIN_EMPTY] = { .state = GARP_APPLICANT_VP }, + [GARP_EVENT_R_EMPTY] = { .state = GARP_APPLICANT_VP }, + [GARP_EVENT_R_LEAVE_IN] = { .state = GARP_APPLICANT_VP }, + [GARP_EVENT_R_LEAVE_EMPTY] = { .state = GARP_APPLICANT_VP }, + [GARP_EVENT_REQ_JOIN] = { .state = GARP_APPLICANT_INVALID }, + [GARP_EVENT_REQ_LEAVE] = { .state = GARP_APPLICANT_AO }, + }, + [GARP_APPLICANT_QP] = { + [GARP_EVENT_TRANSMIT_PDU] = { .state = GARP_APPLICANT_INVALID }, + [GARP_EVENT_R_JOIN_IN] = { .state = GARP_APPLICANT_QP }, + [GARP_EVENT_R_JOIN_EMPTY] = { .state = GARP_APPLICANT_VP }, + [GARP_EVENT_R_EMPTY] = { .state = GARP_APPLICANT_VP }, + [GARP_EVENT_R_LEAVE_IN] = { .state = GARP_APPLICANT_VP }, + [GARP_EVENT_R_LEAVE_EMPTY] = { .state = GARP_APPLICANT_VP }, + [GARP_EVENT_REQ_JOIN] = { .state = GARP_APPLICANT_INVALID }, + [GARP_EVENT_REQ_LEAVE] = { .state = GARP_APPLICANT_QO }, + }, + [GARP_APPLICANT_VO] = { + [GARP_EVENT_TRANSMIT_PDU] = { .state = GARP_APPLICANT_INVALID }, + [GARP_EVENT_R_JOIN_IN] = { .state = GARP_APPLICANT_AO }, + [GARP_EVENT_R_JOIN_EMPTY] = { .state = GARP_APPLICANT_VO }, + [GARP_EVENT_R_EMPTY] = { .state = GARP_APPLICANT_VO }, + [GARP_EVENT_R_LEAVE_IN] = { .state = GARP_APPLICANT_VO }, + [GARP_EVENT_R_LEAVE_EMPTY] = { .state = GARP_APPLICANT_VO }, + [GARP_EVENT_REQ_JOIN] = { .state = GARP_APPLICANT_VP }, + [GARP_EVENT_REQ_LEAVE] = { .state = GARP_APPLICANT_INVALID }, + }, + [GARP_APPLICANT_AO] = { + [GARP_EVENT_TRANSMIT_PDU] = { .state = GARP_APPLICANT_INVALID }, + [GARP_EVENT_R_JOIN_IN] = { .state = GARP_APPLICANT_QO }, + [GARP_EVENT_R_JOIN_EMPTY] = { .state = GARP_APPLICANT_VO }, + [GARP_EVENT_R_EMPTY] = { .state = GARP_APPLICANT_VO }, + [GARP_EVENT_R_LEAVE_IN] = { .state = GARP_APPLICANT_VO }, + [GARP_EVENT_R_LEAVE_EMPTY] = { .state = GARP_APPLICANT_VO }, + [GARP_EVENT_REQ_JOIN] = { .state = GARP_APPLICANT_AP }, + [GARP_EVENT_REQ_LEAVE] = { .state = GARP_APPLICANT_INVALID }, + }, + [GARP_APPLICANT_QO] = { + [GARP_EVENT_TRANSMIT_PDU] = { .state = GARP_APPLICANT_INVALID }, + [GARP_EVENT_R_JOIN_IN] = { .state = GARP_APPLICANT_QO }, + [GARP_EVENT_R_JOIN_EMPTY] = { .state = GARP_APPLICANT_VO }, + [GARP_EVENT_R_EMPTY] = { .state = GARP_APPLICANT_VO }, + [GARP_EVENT_R_LEAVE_IN] = { .state = GARP_APPLICANT_VO }, + [GARP_EVENT_R_LEAVE_EMPTY] = { .state = GARP_APPLICANT_VO }, + [GARP_EVENT_REQ_JOIN] = { .state = GARP_APPLICANT_QP }, + [GARP_EVENT_REQ_LEAVE] = { .state = GARP_APPLICANT_INVALID }, + }, +}; + +static int garp_attr_cmp(const struct garp_attr *attr, + const void *data, u8 len, u8 type) +{ + if (attr->type != type) + return attr->type - type; + if (attr->dlen != len) + return attr->dlen - len; + return memcmp(attr->data, data, len); +} + +static struct garp_attr *garp_attr_lookup(const struct garp_applicant *app, + const void *data, u8 len, u8 type) +{ + struct rb_node *parent = app->gid.rb_node; + struct garp_attr *attr; + int d; + + while (parent) { + attr = rb_entry(parent, struct garp_attr, node); + d = garp_attr_cmp(attr, data, len, type); + if (d > 0) + parent = parent->rb_left; + else if (d < 0) + parent = parent->rb_right; + else + return attr; + } + return NULL; +} + +static struct garp_attr *garp_attr_create(struct garp_applicant *app, + const void *data, u8 len, u8 type) +{ + struct rb_node *parent = NULL, **p = &app->gid.rb_node; + struct garp_attr *attr; + int d; + + while (*p) { + parent = *p; + attr = rb_entry(parent, struct garp_attr, node); + d = garp_attr_cmp(attr, data, len, type); + if (d > 0) + p = &parent->rb_left; + else if (d < 0) + p = &parent->rb_right; + else { + /* The attribute already exists; re-use it. */ + return attr; + } + } + attr = kmalloc(sizeof(*attr) + len, GFP_ATOMIC); + if (!attr) + return attr; + attr->state = GARP_APPLICANT_VO; + attr->type = type; + attr->dlen = len; + memcpy(attr->data, data, len); + + rb_link_node(&attr->node, parent, p); + rb_insert_color(&attr->node, &app->gid); + return attr; +} + +static void garp_attr_destroy(struct garp_applicant *app, struct garp_attr *attr) +{ + rb_erase(&attr->node, &app->gid); + kfree(attr); +} + +static void garp_attr_destroy_all(struct garp_applicant *app) +{ + struct rb_node *node, *next; + struct garp_attr *attr; + + for (node = rb_first(&app->gid); + next = node ? rb_next(node) : NULL, node != NULL; + node = next) { + attr = rb_entry(node, struct garp_attr, node); + garp_attr_destroy(app, attr); + } +} + +static int garp_pdu_init(struct garp_applicant *app) +{ + struct sk_buff *skb; + struct garp_pdu_hdr *gp; + +#define LLC_RESERVE sizeof(struct llc_pdu_un) + skb = alloc_skb(app->dev->mtu + LL_RESERVED_SPACE(app->dev), + GFP_ATOMIC); + if (!skb) + return -ENOMEM; + + skb->dev = app->dev; + skb->protocol = htons(ETH_P_802_2); + skb_reserve(skb, LL_RESERVED_SPACE(app->dev) + LLC_RESERVE); + + gp = __skb_put(skb, sizeof(*gp)); + put_unaligned(htons(GARP_PROTOCOL_ID), &gp->protocol); + + app->pdu = skb; + return 0; +} + +static int garp_pdu_append_end_mark(struct garp_applicant *app) +{ + if (skb_tailroom(app->pdu) < sizeof(u8)) + return -1; + __skb_put_u8(app->pdu, GARP_END_MARK); + return 0; +} + +static void garp_pdu_queue(struct garp_applicant *app) +{ + if (!app->pdu) + return; + + garp_pdu_append_end_mark(app); + garp_pdu_append_end_mark(app); + + llc_pdu_header_init(app->pdu, LLC_PDU_TYPE_U, LLC_SAP_BSPAN, + LLC_SAP_BSPAN, LLC_PDU_CMD); + llc_pdu_init_as_ui_cmd(app->pdu); + llc_mac_hdr_init(app->pdu, app->dev->dev_addr, + app->app->proto.group_address); + + skb_queue_tail(&app->queue, app->pdu); + app->pdu = NULL; +} + +static void garp_queue_xmit(struct garp_applicant *app) +{ + struct sk_buff *skb; + + while ((skb = skb_dequeue(&app->queue))) + dev_queue_xmit(skb); +} + +static int garp_pdu_append_msg(struct garp_applicant *app, u8 attrtype) +{ + struct garp_msg_hdr *gm; + + if (skb_tailroom(app->pdu) < sizeof(*gm)) + return -1; + gm = __skb_put(app->pdu, sizeof(*gm)); + gm->attrtype = attrtype; + garp_cb(app->pdu)->cur_type = attrtype; + return 0; +} + +static int garp_pdu_append_attr(struct garp_applicant *app, + const struct garp_attr *attr, + enum garp_attr_event event) +{ + struct garp_attr_hdr *ga; + unsigned int len; + int err; +again: + if (!app->pdu) { + err = garp_pdu_init(app); + if (err < 0) + return err; + } + + if (garp_cb(app->pdu)->cur_type != attr->type) { + if (garp_cb(app->pdu)->cur_type && + garp_pdu_append_end_mark(app) < 0) + goto queue; + if (garp_pdu_append_msg(app, attr->type) < 0) + goto queue; + } + + len = sizeof(*ga) + attr->dlen; + if (skb_tailroom(app->pdu) < len) + goto queue; + ga = __skb_put(app->pdu, len); + ga->len = len; + ga->event = event; + memcpy(ga->data, attr->data, attr->dlen); + return 0; + +queue: + garp_pdu_queue(app); + goto again; +} + +static void garp_attr_event(struct garp_applicant *app, + struct garp_attr *attr, enum garp_event event) +{ + enum garp_applicant_state state; + + state = garp_applicant_state_table[attr->state][event].state; + if (state == GARP_APPLICANT_INVALID) + return; + + switch (garp_applicant_state_table[attr->state][event].action) { + case GARP_ACTION_NONE: + break; + case GARP_ACTION_S_JOIN_IN: + /* When appending the attribute fails, don't update state in + * order to retry on next TRANSMIT_PDU event. */ + if (garp_pdu_append_attr(app, attr, GARP_JOIN_IN) < 0) + return; + break; + case GARP_ACTION_S_LEAVE_EMPTY: + garp_pdu_append_attr(app, attr, GARP_LEAVE_EMPTY); + /* As a pure applicant, sending a leave message implies that + * the attribute was unregistered and can be destroyed. */ + garp_attr_destroy(app, attr); + return; + default: + WARN_ON(1); + } + + attr->state = state; +} + +int garp_request_join(const struct net_device *dev, + const struct garp_application *appl, + const void *data, u8 len, u8 type) +{ + struct garp_port *port = rtnl_dereference(dev->garp_port); + struct garp_applicant *app = rtnl_dereference(port->applicants[appl->type]); + struct garp_attr *attr; + + spin_lock_bh(&app->lock); + attr = garp_attr_create(app, data, len, type); + if (!attr) { + spin_unlock_bh(&app->lock); + return -ENOMEM; + } + garp_attr_event(app, attr, GARP_EVENT_REQ_JOIN); + spin_unlock_bh(&app->lock); + return 0; +} +EXPORT_SYMBOL_GPL(garp_request_join); + +void garp_request_leave(const struct net_device *dev, + const struct garp_application *appl, + const void *data, u8 len, u8 type) +{ + struct garp_port *port = rtnl_dereference(dev->garp_port); + struct garp_applicant *app = rtnl_dereference(port->applicants[appl->type]); + struct garp_attr *attr; + + spin_lock_bh(&app->lock); + attr = garp_attr_lookup(app, data, len, type); + if (!attr) { + spin_unlock_bh(&app->lock); + return; + } + garp_attr_event(app, attr, GARP_EVENT_REQ_LEAVE); + spin_unlock_bh(&app->lock); +} +EXPORT_SYMBOL_GPL(garp_request_leave); + +static void garp_gid_event(struct garp_applicant *app, enum garp_event event) +{ + struct rb_node *node, *next; + struct garp_attr *attr; + + for (node = rb_first(&app->gid); + next = node ? rb_next(node) : NULL, node != NULL; + node = next) { + attr = rb_entry(node, struct garp_attr, node); + garp_attr_event(app, attr, event); + } +} + +static void garp_join_timer_arm(struct garp_applicant *app) +{ + unsigned long delay; + + delay = get_random_u32_below(msecs_to_jiffies(garp_join_time)); + mod_timer(&app->join_timer, jiffies + delay); +} + +static void garp_join_timer(struct timer_list *t) +{ + struct garp_applicant *app = timer_container_of(app, t, join_timer); + + spin_lock(&app->lock); + garp_gid_event(app, GARP_EVENT_TRANSMIT_PDU); + garp_pdu_queue(app); + spin_unlock(&app->lock); + + garp_queue_xmit(app); + garp_join_timer_arm(app); +} + +static int garp_pdu_parse_end_mark(struct sk_buff *skb) +{ + if (!pskb_may_pull(skb, sizeof(u8))) + return -1; + if (*skb->data == GARP_END_MARK) { + skb_pull(skb, sizeof(u8)); + return -1; + } + return 0; +} + +static int garp_pdu_parse_attr(struct garp_applicant *app, struct sk_buff *skb, + u8 attrtype) +{ + const struct garp_attr_hdr *ga; + struct garp_attr *attr; + enum garp_event event; + unsigned int dlen; + + if (!pskb_may_pull(skb, sizeof(*ga))) + return -1; + ga = (struct garp_attr_hdr *)skb->data; + if (ga->len < sizeof(*ga)) + return -1; + + if (!pskb_may_pull(skb, ga->len)) + return -1; + ga = (struct garp_attr_hdr *)skb->data; + skb_pull(skb, ga->len); + dlen = ga->len - sizeof(*ga); + + if (attrtype > app->app->maxattr) + return 0; + + switch (ga->event) { + case GARP_LEAVE_ALL: + if (dlen != 0) + return -1; + garp_gid_event(app, GARP_EVENT_R_LEAVE_EMPTY); + return 0; + case GARP_JOIN_EMPTY: + event = GARP_EVENT_R_JOIN_EMPTY; + break; + case GARP_JOIN_IN: + event = GARP_EVENT_R_JOIN_IN; + break; + case GARP_LEAVE_EMPTY: + event = GARP_EVENT_R_LEAVE_EMPTY; + break; + case GARP_EMPTY: + event = GARP_EVENT_R_EMPTY; + break; + default: + return 0; + } + + if (dlen == 0) + return -1; + attr = garp_attr_lookup(app, ga->data, dlen, attrtype); + if (attr == NULL) + return 0; + garp_attr_event(app, attr, event); + return 0; +} + +static int garp_pdu_parse_msg(struct garp_applicant *app, struct sk_buff *skb) +{ + const struct garp_msg_hdr *gm; + u8 attrtype; + + if (!pskb_may_pull(skb, sizeof(*gm))) + return -1; + gm = (struct garp_msg_hdr *)skb->data; + if (gm->attrtype == 0) + return -1; + skb_pull(skb, sizeof(*gm)); + attrtype = gm->attrtype; + + while (skb->len > 0) { + if (garp_pdu_parse_attr(app, skb, attrtype) < 0) + return -1; + if (garp_pdu_parse_end_mark(skb) < 0) + break; + } + return 0; +} + +static void garp_pdu_rcv(const struct stp_proto *proto, struct sk_buff *skb, + struct net_device *dev) +{ + struct garp_application *appl = proto->data; + struct garp_port *port; + struct garp_applicant *app; + const struct garp_pdu_hdr *gp; + + port = rcu_dereference(dev->garp_port); + if (!port) + goto err; + app = rcu_dereference(port->applicants[appl->type]); + if (!app) + goto err; + + if (!pskb_may_pull(skb, sizeof(*gp))) + goto err; + gp = (struct garp_pdu_hdr *)skb->data; + if (get_unaligned(&gp->protocol) != htons(GARP_PROTOCOL_ID)) + goto err; + skb_pull(skb, sizeof(*gp)); + + spin_lock(&app->lock); + while (skb->len > 0) { + if (garp_pdu_parse_msg(app, skb) < 0) + break; + if (garp_pdu_parse_end_mark(skb) < 0) + break; + } + spin_unlock(&app->lock); +err: + kfree_skb(skb); +} + +static int garp_init_port(struct net_device *dev) +{ + struct garp_port *port; + + port = kzalloc_obj(*port); + if (!port) + return -ENOMEM; + rcu_assign_pointer(dev->garp_port, port); + return 0; +} + +static void garp_release_port(struct net_device *dev) +{ + struct garp_port *port = rtnl_dereference(dev->garp_port); + unsigned int i; + + for (i = 0; i <= GARP_APPLICATION_MAX; i++) { + if (rtnl_dereference(port->applicants[i])) + return; + } + RCU_INIT_POINTER(dev->garp_port, NULL); + kfree_rcu(port, rcu); +} + +int garp_init_applicant(struct net_device *dev, struct garp_application *appl) +{ + struct garp_applicant *app; + int err; + + ASSERT_RTNL(); + + if (!rtnl_dereference(dev->garp_port)) { + err = garp_init_port(dev); + if (err < 0) + goto err1; + } + + err = -ENOMEM; + app = kzalloc_obj(*app); + if (!app) + goto err2; + + err = dev_mc_add(dev, appl->proto.group_address); + if (err < 0) + goto err3; + + app->dev = dev; + app->app = appl; + app->gid = RB_ROOT; + spin_lock_init(&app->lock); + skb_queue_head_init(&app->queue); + rcu_assign_pointer(dev->garp_port->applicants[appl->type], app); + timer_setup(&app->join_timer, garp_join_timer, 0); + garp_join_timer_arm(app); + return 0; + +err3: + kfree(app); +err2: + garp_release_port(dev); +err1: + return err; +} +EXPORT_SYMBOL_GPL(garp_init_applicant); + +void garp_uninit_applicant(struct net_device *dev, struct garp_application *appl) +{ + struct garp_port *port = rtnl_dereference(dev->garp_port); + struct garp_applicant *app = rtnl_dereference(port->applicants[appl->type]); + + ASSERT_RTNL(); + + RCU_INIT_POINTER(port->applicants[appl->type], NULL); + + /* Delete timer and generate a final TRANSMIT_PDU event to flush out + * all pending messages before the applicant is gone. */ + timer_shutdown_sync(&app->join_timer); + + spin_lock_bh(&app->lock); + garp_gid_event(app, GARP_EVENT_TRANSMIT_PDU); + garp_attr_destroy_all(app); + garp_pdu_queue(app); + spin_unlock_bh(&app->lock); + + garp_queue_xmit(app); + + dev_mc_del(dev, appl->proto.group_address); + kfree_rcu(app, rcu); + garp_release_port(dev); +} +EXPORT_SYMBOL_GPL(garp_uninit_applicant); + +int garp_register_application(struct garp_application *appl) +{ + appl->proto.rcv = garp_pdu_rcv; + appl->proto.data = appl; + return stp_proto_register(&appl->proto); +} +EXPORT_SYMBOL_GPL(garp_register_application); + +void garp_unregister_application(struct garp_application *appl) +{ + stp_proto_unregister(&appl->proto); +} +EXPORT_SYMBOL_GPL(garp_unregister_application); -- cgit v1.3.1