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tipc: move received discovery data evaluation inside node.c
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The node lock is currently grabbed and and released in the function
tipc_disc_rcv() in the file discover.c. As a preparation for the next
commits, we need to move this node lock handling, along with the code
area it is covering, to node.c.

This commit introduces this change.

Tested-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Jon Paul Maloy authored and David S. Miller committed Jul 31, 2015
1 parent 662921c commit cf14881
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Showing 3 changed files with 127 additions and 123 deletions.
116 changes: 20 additions & 96 deletions net/tipc/discover.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -120,29 +120,24 @@ static void disc_dupl_alert(struct tipc_bearer *b_ptr, u32 node_addr,
* @buf: buffer containing message
* @bearer: bearer that message arrived on
*/
void tipc_disc_rcv(struct net *net, struct sk_buff *buf,
void tipc_disc_rcv(struct net *net, struct sk_buff *skb,
struct tipc_bearer *bearer)
{
struct tipc_net *tn = net_generic(net, tipc_net_id);
struct tipc_node *node;
struct tipc_media_addr maddr;
struct sk_buff *rbuf;
struct tipc_msg *msg = buf_msg(buf);
u32 ddom = msg_dest_domain(msg);
u32 onode = msg_prevnode(msg);
u32 net_id = msg_bc_netid(msg);
u32 mtyp = msg_type(msg);
u32 signature = msg_node_sig(msg);
u16 caps = msg_node_capabilities(msg);
bool addr_match = false;
bool sign_match = false;
bool link_up = false;
bool accept_addr = false;
bool accept_sign = false;
struct sk_buff *rskb;
struct tipc_msg *hdr = buf_msg(skb);
u32 ddom = msg_dest_domain(hdr);
u32 onode = msg_prevnode(hdr);
u32 net_id = msg_bc_netid(hdr);
u32 mtyp = msg_type(hdr);
u32 signature = msg_node_sig(hdr);
u16 caps = msg_node_capabilities(hdr);
bool respond = false;
bool dupl_addr = false;

bearer->media->msg2addr(bearer, &maddr, msg_media_addr(msg));
kfree_skb(buf);
bearer->media->msg2addr(bearer, &maddr, msg_media_addr(hdr));
kfree_skb(skb);

/* Ensure message from node is valid and communication is permitted */
if (net_id != tn->net_id)
Expand All @@ -164,91 +159,20 @@ void tipc_disc_rcv(struct net *net, struct sk_buff *buf,
if (!tipc_in_scope(bearer->domain, onode))
return;

node = tipc_node_create(net, onode);
if (!node)
return;
tipc_node_lock(node);
node->capabilities = caps;

/* Prepare to validate requesting node's signature and media address */
sign_match = (signature == node->signature);
tipc_node_check_dest(node, bearer, &link_up, &addr_match, &maddr);

/* These three flags give us eight permutations: */

if (sign_match && addr_match && link_up) {
/* All is fine. Do nothing. */
} else if (sign_match && addr_match && !link_up) {
/* Respond. The link will come up in due time */
respond = true;
} else if (sign_match && !addr_match && link_up) {
/* Peer has changed i/f address without rebooting.
* If so, the link will reset soon, and the next
* discovery will be accepted. So we can ignore it.
* It may also be an cloned or malicious peer having
* chosen the same node address and signature as an
* existing one.
* Ignore requests until the link goes down, if ever.
*/
tipc_node_check_dest(net, onode, bearer, caps, signature,
&maddr, &respond, &dupl_addr);
if (dupl_addr)
disc_dupl_alert(bearer, onode, &maddr);
} else if (sign_match && !addr_match && !link_up) {
/* Peer link has changed i/f address without rebooting.
* It may also be a cloned or malicious peer; we can't
* distinguish between the two.
* The signature is correct, so we must accept.
*/
accept_addr = true;
respond = true;
} else if (!sign_match && addr_match && link_up) {
/* Peer node rebooted. Two possibilities:
* - Delayed re-discovery; this link endpoint has already
* reset and re-established contact with the peer, before
* receiving a discovery message from that node.
* (The peer happened to receive one from this node first).
* - The peer came back so fast that our side has not
* discovered it yet. Probing from this side will soon
* reset the link, since there can be no working link
* endpoint at the peer end, and the link will re-establish.
* Accept the signature, since it comes from a known peer.
*/
accept_sign = true;
} else if (!sign_match && addr_match && !link_up) {
/* The peer node has rebooted.
* Accept signature, since it is a known peer.
*/
accept_sign = true;
respond = true;
} else if (!sign_match && !addr_match && link_up) {
/* Peer rebooted with new address, or a new/duplicate peer.
* Ignore until the link goes down, if ever.
*/
disc_dupl_alert(bearer, onode, &maddr);
} else if (!sign_match && !addr_match && !link_up) {
/* Peer rebooted with new address, or it is a new peer.
* Accept signature and address.
*/
accept_sign = true;
accept_addr = true;
respond = true;
}

if (accept_sign)
node->signature = signature;

if (accept_addr && !tipc_node_update_dest(node, bearer, &maddr))
respond = false;

/* Send response, if necessary */
if (respond && (mtyp == DSC_REQ_MSG)) {
rbuf = tipc_buf_acquire(MAX_H_SIZE);
if (rbuf) {
tipc_disc_init_msg(net, rbuf, DSC_RESP_MSG, bearer);
tipc_bearer_send(net, bearer->identity, rbuf, &maddr);
kfree_skb(rbuf);
rskb = tipc_buf_acquire(MAX_H_SIZE);
if (rskb) {
tipc_disc_init_msg(net, rskb, DSC_RESP_MSG, bearer);
tipc_bearer_send(net, bearer->identity, rskb, &maddr);
kfree_skb(rskb);
}
}
tipc_node_unlock(node);
tipc_node_put(node);
}

/**
Expand Down
123 changes: 102 additions & 21 deletions net/tipc/node.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -138,7 +138,7 @@ struct tipc_node *tipc_node_find(struct net *net, u32 addr)
return NULL;
}

struct tipc_node *tipc_node_create(struct net *net, u32 addr)
struct tipc_node *tipc_node_create(struct net *net, u32 addr, u16 capabilities)
{
struct tipc_net *tn = net_generic(net, tipc_net_id);
struct tipc_node *n_ptr, *temp_node;
Expand All @@ -154,6 +154,7 @@ struct tipc_node *tipc_node_create(struct net *net, u32 addr)
}
n_ptr->addr = addr;
n_ptr->net = net;
n_ptr->capabilities = capabilities;
kref_init(&n_ptr->kref);
spin_lock_init(&n_ptr->lock);
INIT_HLIST_NODE(&n_ptr->hash);
Expand Down Expand Up @@ -422,38 +423,118 @@ bool tipc_node_is_up(struct tipc_node *n)
return n->active_links[0] != INVALID_BEARER_ID;
}

void tipc_node_check_dest(struct tipc_node *n, struct tipc_bearer *b,
bool *link_up, bool *addr_match,
struct tipc_media_addr *maddr)
void tipc_node_check_dest(struct net *net, u32 onode,
struct tipc_bearer *b,
u16 capabilities, u32 signature,
struct tipc_media_addr *maddr,
bool *respond, bool *dupl_addr)
{
struct tipc_link *l = n->links[b->identity].link;
struct tipc_media_addr *curr = &n->links[b->identity].maddr;
struct tipc_node *n;
struct tipc_link *l;
struct tipc_media_addr *curr_maddr;
struct sk_buff_head *inputq;
bool addr_match = false;
bool sign_match = false;
bool link_up = false;
bool accept_addr = false;

*dupl_addr = false;
*respond = false;

n = tipc_node_create(net, onode, capabilities);
if (!n)
return;

*link_up = l && tipc_link_is_up(l);
*addr_match = l && !memcmp(curr, maddr, sizeof(*maddr));
}
tipc_node_lock(n);

bool tipc_node_update_dest(struct tipc_node *n, struct tipc_bearer *b,
struct tipc_media_addr *maddr)
{
struct tipc_link *l = n->links[b->identity].link;
struct tipc_media_addr *curr = &n->links[b->identity].maddr;
struct sk_buff_head *inputq = &n->links[b->identity].inputq;
curr_maddr = &n->links[b->identity].maddr;
inputq = &n->links[b->identity].inputq;

/* Prepare to validate requesting node's signature and media address */
l = n->links[b->identity].link;
link_up = l && tipc_link_is_up(l);
addr_match = l && !memcmp(curr_maddr, maddr, sizeof(*maddr));
sign_match = (signature == n->signature);

/* These three flags give us eight permutations: */

if (sign_match && addr_match && link_up) {
/* All is fine. Do nothing. */
} else if (sign_match && addr_match && !link_up) {
/* Respond. The link will come up in due time */
*respond = true;
} else if (sign_match && !addr_match && link_up) {
/* Peer has changed i/f address without rebooting.
* If so, the link will reset soon, and the next
* discovery will be accepted. So we can ignore it.
* It may also be an cloned or malicious peer having
* chosen the same node address and signature as an
* existing one.
* Ignore requests until the link goes down, if ever.
*/
*dupl_addr = true;
} else if (sign_match && !addr_match && !link_up) {
/* Peer link has changed i/f address without rebooting.
* It may also be a cloned or malicious peer; we can't
* distinguish between the two.
* The signature is correct, so we must accept.
*/
accept_addr = true;
*respond = true;
} else if (!sign_match && addr_match && link_up) {
/* Peer node rebooted. Two possibilities:
* - Delayed re-discovery; this link endpoint has already
* reset and re-established contact with the peer, before
* receiving a discovery message from that node.
* (The peer happened to receive one from this node first).
* - The peer came back so fast that our side has not
* discovered it yet. Probing from this side will soon
* reset the link, since there can be no working link
* endpoint at the peer end, and the link will re-establish.
* Accept the signature, since it comes from a known peer.
*/
n->signature = signature;
} else if (!sign_match && addr_match && !link_up) {
/* The peer node has rebooted.
* Accept signature, since it is a known peer.
*/
n->signature = signature;
*respond = true;
} else if (!sign_match && !addr_match && link_up) {
/* Peer rebooted with new address, or a new/duplicate peer.
* Ignore until the link goes down, if ever.
*/
*dupl_addr = true;
} else if (!sign_match && !addr_match && !link_up) {
/* Peer rebooted with new address, or it is a new peer.
* Accept signature and address.
*/
n->signature = signature;
accept_addr = true;
*respond = true;
}

if (!accept_addr)
goto exit;

/* Now create new link if not already existing */
if (!l) {
l = tipc_link_create(n, b, maddr, inputq, &n->bclink.namedq);
if (!l)
return false;
if (!l) {
*respond = false;
goto exit;
}
tipc_node_calculate_timer(n, l);
if (n->link_cnt == 1) {
if (n->link_cnt == 1)
if (!mod_timer(&n->timer, jiffies + n->keepalive_intv))
tipc_node_get(n);
}
}
memcpy(&l->media_addr, maddr, sizeof(*maddr));
memcpy(curr, maddr, sizeof(*maddr));
memcpy(curr_maddr, maddr, sizeof(*maddr));
tipc_node_link_down(n, b->identity);
return true;
exit:
tipc_node_unlock(n);
tipc_node_put(n);
}

void tipc_node_delete_links(struct net *net, int bearer_id)
Expand Down
11 changes: 5 additions & 6 deletions net/tipc/node.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -147,13 +147,12 @@ struct tipc_node {

struct tipc_node *tipc_node_find(struct net *net, u32 addr);
void tipc_node_put(struct tipc_node *node);
struct tipc_node *tipc_node_create(struct net *net, u32 addr);
void tipc_node_stop(struct net *net);
void tipc_node_check_dest(struct tipc_node *n, struct tipc_bearer *bearer,
bool *link_up, bool *addr_match,
struct tipc_media_addr *maddr);
bool tipc_node_update_dest(struct tipc_node *n, struct tipc_bearer *bearer,
struct tipc_media_addr *maddr);
void tipc_node_check_dest(struct net *net, u32 onode,
struct tipc_bearer *bearer,
u16 capabilities, u32 signature,
struct tipc_media_addr *maddr,
bool *respond, bool *dupl_addr);
void tipc_node_delete_links(struct net *net, int bearer_id);
void tipc_node_attach_link(struct tipc_node *n_ptr, struct tipc_link *l_ptr);
void tipc_node_detach_link(struct tipc_node *n_ptr, struct tipc_link *l_ptr);
Expand Down

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