Re: netgraph memory trouble

From: Roman Kurakin (rik_at_cronyx.ru)
Date: 08/19/05

  • Next message: Paul Khavkine: "Reading raw ethernet" 
    Date: Fri, 19 Aug 2005 21:43:43 +0400
To: David Vos <david.vos@gmail.com>

    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
    >_______________________________________________
    >freebsd-net@freebsd.org mailing list
    >http://lists.freebsd.org/mailman/listinfo/freebsd-net
    >To unsubscribe, send any mail to "freebsd-net-unsubscribe@freebsd.org"
    >
    >
    >

    _______________________________________________
    freebsd-net@freebsd.org mailing list
    http://lists.freebsd.org/mailman/listinfo/freebsd-net
    To unsubscribe, send any mail to "freebsd-net-unsubscribe@freebsd.org"

  • Next message: Paul Khavkine: "Reading raw ethernet"