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48d2ab609b
As reported by Lennert the MPLS GSO code is failing to properly segment large packets. There are a couple of problems: 1. the inner protocol is not set so the gso segment functions for inner protocol layers are not getting run, and 2 MPLS labels for packets that use the "native" (non-OVS) MPLS code are not properly accounted for in mpls_gso_segment. The MPLS GSO code was added for OVS. It is re-using skb_mac_gso_segment to call the gso segment functions for the higher layer protocols. That means skb_mac_gso_segment is called twice -- once with the network protocol set to MPLS and again with the network protocol set to the inner protocol. This patch sets the inner skb protocol addressing item 1 above and sets the network_header and inner_network_header to mark where the MPLS labels start and end. The MPLS code in OVS is also updated to set the two network markers. >From there the MPLS GSO code uses the difference between the network header and the inner network header to know the size of the MPLS header that was pushed. It then pulls the MPLS header, resets the mac_len and protocol for the inner protocol and then calls skb_mac_gso_segment to segment the skb. Afterward the inner protocol segmentation is done the skb protocol is set to mpls for each segment and the network and mac headers restored. Reported-by: Lennert Buytenhek <buytenh@wantstofly.org> Signed-off-by: David Ahern <dsa@cumulusnetworks.com> Signed-off-by: David S. Miller <davem@davemloft.net>
111 lines
2.5 KiB
C
111 lines
2.5 KiB
C
/*
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* MPLS GSO Support
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*
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* Authors: Simon Horman (horms@verge.net.au)
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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* Based on: GSO portions of net/ipv4/gre.c
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/err.h>
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#include <linux/module.h>
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#include <linux/netdev_features.h>
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#include <linux/netdevice.h>
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#include <linux/skbuff.h>
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static struct sk_buff *mpls_gso_segment(struct sk_buff *skb,
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netdev_features_t features)
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{
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struct sk_buff *segs = ERR_PTR(-EINVAL);
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u16 mac_offset = skb->mac_header;
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netdev_features_t mpls_features;
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u16 mac_len = skb->mac_len;
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__be16 mpls_protocol;
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unsigned int mpls_hlen;
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skb_reset_network_header(skb);
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mpls_hlen = skb_inner_network_header(skb) - skb_network_header(skb);
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if (unlikely(!pskb_may_pull(skb, mpls_hlen)))
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goto out;
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/* Setup inner SKB. */
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mpls_protocol = skb->protocol;
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skb->protocol = skb->inner_protocol;
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__skb_pull(skb, mpls_hlen);
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skb->mac_len = 0;
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skb_reset_mac_header(skb);
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/* Segment inner packet. */
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mpls_features = skb->dev->mpls_features & features;
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segs = skb_mac_gso_segment(skb, mpls_features);
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if (IS_ERR_OR_NULL(segs)) {
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skb_gso_error_unwind(skb, mpls_protocol, mpls_hlen, mac_offset,
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mac_len);
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goto out;
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}
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skb = segs;
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mpls_hlen += mac_len;
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do {
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skb->mac_len = mac_len;
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skb->protocol = mpls_protocol;
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skb_reset_inner_network_header(skb);
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__skb_push(skb, mpls_hlen);
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skb_reset_mac_header(skb);
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skb_set_network_header(skb, mac_len);
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} while ((skb = skb->next));
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out:
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return segs;
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}
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static struct packet_offload mpls_mc_offload __read_mostly = {
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.type = cpu_to_be16(ETH_P_MPLS_MC),
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.priority = 15,
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.callbacks = {
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.gso_segment = mpls_gso_segment,
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},
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};
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static struct packet_offload mpls_uc_offload __read_mostly = {
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.type = cpu_to_be16(ETH_P_MPLS_UC),
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.priority = 15,
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.callbacks = {
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.gso_segment = mpls_gso_segment,
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},
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};
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static int __init mpls_gso_init(void)
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{
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pr_info("MPLS GSO support\n");
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dev_add_offload(&mpls_uc_offload);
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dev_add_offload(&mpls_mc_offload);
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return 0;
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}
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static void __exit mpls_gso_exit(void)
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{
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dev_remove_offload(&mpls_uc_offload);
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dev_remove_offload(&mpls_mc_offload);
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}
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module_init(mpls_gso_init);
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module_exit(mpls_gso_exit);
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MODULE_DESCRIPTION("MPLS GSO support");
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MODULE_AUTHOR("Simon Horman (horms@verge.net.au)");
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MODULE_LICENSE("GPL");
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