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Hi,
On Tue, 16 Sep 2003, Stephen Hemminger wrote:
> Get rid of skb_linearize warnings, by using may_pull to get the
> header where needed.
>
I am not sure if the calls of skb_share_check() are necessary, because
the ip_rcv has already done the skb share check for receiving packets. I
don't know if other netfilter hooks can inject a shared skb.
Yes, we need to change IPVS to handle nonlinear skb as soon as possible,
and remove these skb_linearize warnings.
Thanks,
Wensong
> diff -Nru a/net/ipv4/ipvs/ip_vs_app.c b/net/ipv4/ipvs/ip_vs_app.c
> --- a/net/ipv4/ipvs/ip_vs_app.c Tue Sep 16 14:11:17 2003
> +++ b/net/ipv4/ipvs/ip_vs_app.c Tue Sep 16 14:11:17 2003
> @@ -382,6 +382,10 @@
> return 0;
>
> iph = skb->nh.iph;
> + if (!pskb_may_pull(skb, (iph->ihl*4)+sizeof(*th)))
> + return 0;
> +
> + iph = skb->nh.iph;
> th = (struct tcphdr *)&(((char *)iph)[iph->ihl*4]);
>
> /*
> @@ -436,6 +440,10 @@
> * this ip_vs_conn.
> */
> if ((app = cp->app) == NULL)
> + return 0;
> +
> + iph = skb->nh.iph;
> + if (!pskb_may_pull(skb, (iph->ihl*4)+sizeof(*th)))
> return 0;
>
> iph = skb->nh.iph;
> diff -Nru a/net/ipv4/ipvs/ip_vs_core.c b/net/ipv4/ipvs/ip_vs_core.c
> --- a/net/ipv4/ipvs/ip_vs_core.c Tue Sep 16 14:11:17 2003
> +++ b/net/ipv4/ipvs/ip_vs_core.c Tue Sep 16 14:11:17 2003
> @@ -526,11 +526,11 @@
> *skb_p = skb;
> }
>
> - if (skb_is_nonlinear(skb)) {
> - if (skb_linearize(skb, GFP_ATOMIC) != 0)
> - return NF_DROP;
> - ip_send_check(skb->nh.iph);
> - }
> + if (!(skb = skb_share_check(skb, GFP_ATOMIC)))
> + return NF_STOLEN;
> +
> + if (!pskb_may_pull(skb, sizeof(*iph) + sizeof(*icmph)))
> + return NF_DROP;
>
> iph = skb->nh.iph;
> ihl = iph->ihl << 2;
> @@ -726,11 +726,12 @@
> * do final checksum checking.
> */
>
> - if (unlikely(cp->app && !pp->slave && skb_is_nonlinear(skb))) {
> - if (skb_linearize(skb, GFP_ATOMIC) != 0) {
> + if (unlikely(cp->app && !pp->slave)) {
> + if (!(skb = skb_share_check(skb, GFP_ATOMIC))) {
> ip_vs_conn_put(cp);
> - return NF_DROP;
> + return NF_STOLEN;
> }
> +
> iph = skb->nh.iph;
> h.raw = (char*) iph + ihl;
> }
> @@ -816,12 +817,13 @@
> int rc;
>
> *related = 1;
> - if (skb_is_nonlinear(skb)) {
> - if (skb_linearize(skb, GFP_ATOMIC) != 0)
> - return NF_DROP;
> - ip_send_check(skb->nh.iph);
> - }
> -
> + if (!pskb_may_pull(skb, sizeof(*iph)))
> + return NF_DROP;
> +
> + iph = skb->nh.iph;
> + if (!pskb_may_pull(skb, iph->ihl*4 + sizeof(*icmph)))
> + return NF_DROP;
> +
> iph = skb->nh.iph;
> icmph = (struct icmphdr *)((char *)iph+(iph->ihl<<2));
> len = ntohs(iph->tot_len) - (iph->ihl<<2);
> diff -Nru a/net/ipv4/ipvs/ip_vs_xmit.c b/net/ipv4/ipvs/ip_vs_xmit.c
> --- a/net/ipv4/ipvs/ip_vs_xmit.c Tue Sep 16 14:11:17 2003
> +++ b/net/ipv4/ipvs/ip_vs_xmit.c Tue Sep 16 14:11:17 2003
> @@ -265,13 +265,20 @@
> */
>
> if (unlikely(cp->app && !pp->slave)) {
> - if (skb_is_nonlinear(skb) &&
> - skb_linearize(skb, GFP_ATOMIC) != 0)
> - return NF_DROP;
> + if (!(skb = skb_share_check(skb, GFP_ATOMIC)))
> + return NF_STOLEN;
> +
> }
>
> + if (!pskb_may_pull(skb, sizeof(*iph)))
> + goto tx_error;
> +
> iph = skb->nh.iph;
> ihl = iph->ihl << 2;
> + if (!pskb_may_pull(skb, sizeof(*iph) + ihl))
> + goto tx_error;
> +
> + iph = skb->nh.iph;
> h.raw = (char*) iph + ihl;
> size = ntohs(iph->tot_len) - ihl;
>
>
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