diff options
Diffstat (limited to 'net/tipc/msg.c')
| -rw-r--r-- | net/tipc/msg.c | 51 |
1 files changed, 44 insertions, 7 deletions
diff --git a/net/tipc/msg.c b/net/tipc/msg.c index b0d07b35909d..55d8ba92291d 100644 --- a/net/tipc/msg.c +++ b/net/tipc/msg.c @@ -251,20 +251,23 @@ bool tipc_msg_validate(struct sk_buff **_skb) * @pktmax: Max packet size that can be used * @list: Buffer or chain of buffers to be returned to caller * + * Note that the recursive call we are making here is safe, since it can + * logically go only one further level down. + * * Returns message data size or errno: -ENOMEM, -EFAULT */ -int tipc_msg_build(struct tipc_msg *mhdr, struct msghdr *m, - int offset, int dsz, int pktmax, struct sk_buff_head *list) +int tipc_msg_build(struct tipc_msg *mhdr, struct msghdr *m, int offset, + int dsz, int pktmax, struct sk_buff_head *list) { int mhsz = msg_hdr_sz(mhdr); + struct tipc_msg pkthdr; int msz = mhsz + dsz; - int pktno = 1; - int pktsz; int pktrem = pktmax; - int drem = dsz; - struct tipc_msg pkthdr; struct sk_buff *skb; + int drem = dsz; + int pktno = 1; char *pktpos; + int pktsz; int rc; msg_set_size(mhdr, msz); @@ -272,8 +275,18 @@ int tipc_msg_build(struct tipc_msg *mhdr, struct msghdr *m, /* No fragmentation needed? */ if (likely(msz <= pktmax)) { skb = tipc_buf_acquire(msz, GFP_KERNEL); - if (unlikely(!skb)) + + /* Fall back to smaller MTU if node local message */ + if (unlikely(!skb)) { + if (pktmax != MAX_MSG_SIZE) + return -ENOMEM; + rc = tipc_msg_build(mhdr, m, offset, dsz, FB_MTU, list); + if (rc != dsz) + return rc; + if (tipc_msg_assemble(list)) + return dsz; return -ENOMEM; + } skb_orphan(skb); __skb_queue_tail(list, skb); skb_copy_to_linear_data(skb, mhdr, mhsz); @@ -589,6 +602,30 @@ bool tipc_msg_lookup_dest(struct net *net, struct sk_buff *skb, int *err) return true; } +/* tipc_msg_assemble() - assemble chain of fragments into one message + */ +bool tipc_msg_assemble(struct sk_buff_head *list) +{ + struct sk_buff *skb, *tmp = NULL; + + if (skb_queue_len(list) == 1) + return true; + + while ((skb = __skb_dequeue(list))) { + skb->next = NULL; + if (tipc_buf_append(&tmp, &skb)) { + __skb_queue_tail(list, skb); + return true; + } + if (!tmp) + break; + } + __skb_queue_purge(list); + __skb_queue_head_init(list); + pr_warn("Failed do assemble buffer\n"); + return false; +} + /* tipc_msg_reassemble() - clone a buffer chain of fragments and * reassemble the clones into one message */ |