netgraph memory trouble

[Roman Kurakin]

It seems reasonable. If no one take care of it, let me know
I'll commit it.

rik

David Vos wrote:

>I have been playing with the netgraph ng_split node.  I discovered
>that if I sent packets to it, after a period of time, I could no
>longer use netgraph.  If I tried to use ngctl, I got an error back
>saying that it could not allocate memory to send a message.  This also
>meant that I could not shutdown my nodes (because that required
>sending a message) and had to reboot my machine to start using
>netgraph again.
>
>vmstat -m would show netgraph_item having 128 items in use.
>
>I am sending data to the split node using the macro
>"NG_FWD_ITEM_HOOK".  Since this macro nulls out the item pointer, I
>assume it takes full responsibility to free the item if something
>fails.
>
>The item then gets sent on to the function:
>static int
>ng_split_rcvdata(hook_p hook, item_p item)
>{
>	const priv_p	priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
>	int		error = 0;
>
>	if (hook == priv->out) {
>		printf("ng_split: got packet from out hook!\n");
>		NG_FREE_ITEM(item);
>		error = EINVAL;
>	} else if ((hook == priv->in) && (priv->mixed != NULL)) {
>		NG_FWD_ITEM_HOOK(error, item, priv->mixed);
>	} else if ((hook == priv->mixed) && (priv->out != NULL)) {
>		NG_FWD_ITEM_HOOK(error, item, priv->out);
>	}
>
>	return (error);
>}
>
>
>Unfortunately, if priv->mixed or priv->out are NULL, then there is no
>error  generated, and the item is not freed.
>
>I modified the function to be:
>        printf("ng_split: got packet hook=%x, priv->in=%x, priv->out=%x
>                   priv->mixed=%x\n", hook, priv->in, priv->out, priv->mixed);
>
>        if (hook == priv->out) {
>                printf("ng_split: got packet from out hook!\n");
>                NG_FREE_ITEM(item);
>                error = EINVAL;
>        } else if ((hook == priv->in) && (priv->mixed != NULL)) {
>                NG_FWD_ITEM_HOOK(error, item, priv->mixed);
>        } else if ((hook == priv->mixed) && (priv->out != NULL)) {
>                NG_FWD_ITEM_HOOK(error, item, priv->out);
>        } else {
>                printf("ng_split: got packet from unknown hook, or
>output hook is null\n");
>                NG_FREE_ITEM(item);
>                error = EINVAL;
>        }
>
>In /var/log/messages, I get:
>Aug 18 15:31:50 foo kernel: ng_split: got packet hook=c53f6800,
>priv->in=c53f6800, priv->out=c53f8c80 priv->mixed=0
>Aug 18 15:31:50 foo kernel: ng_split: got packet from unknown hook, or
>output hook is null
>
>After making this modification to the code, I have not experienced any
>of the memory problems mentioned above.
>
>
>My conclusion is that an else clause needs to be added to the branches
>in the ng_split_rcfdata() function.
>
>I am using FreeBSD 5.4-RELEASE #1.
>
>
>David
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>  
>