![Cong Wang](/assets/img/avatar_default.png)
In vlan_insert_tag(), we insert a 4-byte VLAN header _after_ mac header: memmove(skb->data, skb->data + VLAN_HLEN, 2 * ETH_ALEN); ... veth->h_vlan_proto = htons(ETH_P_8021Q); ... veth->h_vlan_TCI = htons(vlan_tci); so after it, we should recompute the checksum to include these 4 bytes. skb->data still points to the mac header, therefore VLAN header is at (2 * ETH_ALEN = 12) bytes after it, not (ETH_HLEN = 14) bytes. This can also be observed via tcpdump: 0x0000: ffff ffff ffff 5254 005d 6f6e 8100 000a 0x0010: 0806 0001 0800 0604 0001 5254 005d 6f6e 0x0020: c0a8 026e 0000 0000 0000 c0a8 0282 Similar for __pop_vlan_tci(), the vlan header we remove is the one overwritten in: memmove(skb->data + VLAN_HLEN, skb->data, 2 * ETH_ALEN); Therefore the VLAN_HLEN = 4 bytes after 2 * ETH_ALEN is the part we want to sub from checksum. Cc: David S. Miller <davem@davemloft.net> Cc: Jesse Gross <jesse@nicira.com> Signed-off-by: Cong Wang <amwang@redhat.com> Signed-off-by: Jesse Gross <jesse@nicira.com>
533 lines
12 KiB
C
533 lines
12 KiB
C
/*
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* Copyright (c) 2007-2012 Nicira, Inc.
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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 version 2 of the GNU General Public
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* License as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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* 02110-1301, USA
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/skbuff.h>
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#include <linux/in.h>
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#include <linux/ip.h>
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#include <linux/openvswitch.h>
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#include <linux/tcp.h>
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#include <linux/udp.h>
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#include <linux/in6.h>
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#include <linux/if_arp.h>
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#include <linux/if_vlan.h>
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#include <net/ip.h>
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#include <net/ipv6.h>
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#include <net/checksum.h>
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#include <net/dsfield.h>
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#include "datapath.h"
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#include "vport.h"
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static int do_execute_actions(struct datapath *dp, struct sk_buff *skb,
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const struct nlattr *attr, int len, bool keep_skb);
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static int make_writable(struct sk_buff *skb, int write_len)
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{
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if (!skb_cloned(skb) || skb_clone_writable(skb, write_len))
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return 0;
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return pskb_expand_head(skb, 0, 0, GFP_ATOMIC);
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}
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/* remove VLAN header from packet and update csum accordingly. */
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static int __pop_vlan_tci(struct sk_buff *skb, __be16 *current_tci)
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{
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struct vlan_hdr *vhdr;
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int err;
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err = make_writable(skb, VLAN_ETH_HLEN);
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if (unlikely(err))
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return err;
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if (skb->ip_summed == CHECKSUM_COMPLETE)
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skb->csum = csum_sub(skb->csum, csum_partial(skb->data
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+ (2 * ETH_ALEN), VLAN_HLEN, 0));
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vhdr = (struct vlan_hdr *)(skb->data + ETH_HLEN);
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*current_tci = vhdr->h_vlan_TCI;
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memmove(skb->data + VLAN_HLEN, skb->data, 2 * ETH_ALEN);
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__skb_pull(skb, VLAN_HLEN);
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vlan_set_encap_proto(skb, vhdr);
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skb->mac_header += VLAN_HLEN;
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skb_reset_mac_len(skb);
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return 0;
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}
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static int pop_vlan(struct sk_buff *skb)
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{
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__be16 tci;
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int err;
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if (likely(vlan_tx_tag_present(skb))) {
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skb->vlan_tci = 0;
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} else {
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if (unlikely(skb->protocol != htons(ETH_P_8021Q) ||
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skb->len < VLAN_ETH_HLEN))
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return 0;
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err = __pop_vlan_tci(skb, &tci);
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if (err)
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return err;
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}
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/* move next vlan tag to hw accel tag */
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if (likely(skb->protocol != htons(ETH_P_8021Q) ||
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skb->len < VLAN_ETH_HLEN))
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return 0;
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err = __pop_vlan_tci(skb, &tci);
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if (unlikely(err))
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return err;
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__vlan_hwaccel_put_tag(skb, ntohs(tci));
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return 0;
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}
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static int push_vlan(struct sk_buff *skb, const struct ovs_action_push_vlan *vlan)
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{
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if (unlikely(vlan_tx_tag_present(skb))) {
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u16 current_tag;
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/* push down current VLAN tag */
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current_tag = vlan_tx_tag_get(skb);
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if (!__vlan_put_tag(skb, current_tag))
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return -ENOMEM;
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if (skb->ip_summed == CHECKSUM_COMPLETE)
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skb->csum = csum_add(skb->csum, csum_partial(skb->data
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+ (2 * ETH_ALEN), VLAN_HLEN, 0));
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}
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__vlan_hwaccel_put_tag(skb, ntohs(vlan->vlan_tci) & ~VLAN_TAG_PRESENT);
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return 0;
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}
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static int set_eth_addr(struct sk_buff *skb,
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const struct ovs_key_ethernet *eth_key)
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{
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int err;
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err = make_writable(skb, ETH_HLEN);
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if (unlikely(err))
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return err;
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memcpy(eth_hdr(skb)->h_source, eth_key->eth_src, ETH_ALEN);
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memcpy(eth_hdr(skb)->h_dest, eth_key->eth_dst, ETH_ALEN);
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return 0;
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}
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static void set_ip_addr(struct sk_buff *skb, struct iphdr *nh,
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__be32 *addr, __be32 new_addr)
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{
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int transport_len = skb->len - skb_transport_offset(skb);
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if (nh->protocol == IPPROTO_TCP) {
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if (likely(transport_len >= sizeof(struct tcphdr)))
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inet_proto_csum_replace4(&tcp_hdr(skb)->check, skb,
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*addr, new_addr, 1);
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} else if (nh->protocol == IPPROTO_UDP) {
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if (likely(transport_len >= sizeof(struct udphdr))) {
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struct udphdr *uh = udp_hdr(skb);
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if (uh->check || skb->ip_summed == CHECKSUM_PARTIAL) {
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inet_proto_csum_replace4(&uh->check, skb,
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*addr, new_addr, 1);
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if (!uh->check)
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uh->check = CSUM_MANGLED_0;
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}
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}
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}
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csum_replace4(&nh->check, *addr, new_addr);
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skb->rxhash = 0;
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*addr = new_addr;
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}
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static void update_ipv6_checksum(struct sk_buff *skb, u8 l4_proto,
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__be32 addr[4], const __be32 new_addr[4])
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{
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int transport_len = skb->len - skb_transport_offset(skb);
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if (l4_proto == IPPROTO_TCP) {
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if (likely(transport_len >= sizeof(struct tcphdr)))
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inet_proto_csum_replace16(&tcp_hdr(skb)->check, skb,
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addr, new_addr, 1);
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} else if (l4_proto == IPPROTO_UDP) {
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if (likely(transport_len >= sizeof(struct udphdr))) {
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struct udphdr *uh = udp_hdr(skb);
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if (uh->check || skb->ip_summed == CHECKSUM_PARTIAL) {
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inet_proto_csum_replace16(&uh->check, skb,
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addr, new_addr, 1);
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if (!uh->check)
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uh->check = CSUM_MANGLED_0;
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}
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}
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}
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}
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static void set_ipv6_addr(struct sk_buff *skb, u8 l4_proto,
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__be32 addr[4], const __be32 new_addr[4],
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bool recalculate_csum)
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{
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if (recalculate_csum)
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update_ipv6_checksum(skb, l4_proto, addr, new_addr);
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skb->rxhash = 0;
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memcpy(addr, new_addr, sizeof(__be32[4]));
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}
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static void set_ipv6_tc(struct ipv6hdr *nh, u8 tc)
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{
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nh->priority = tc >> 4;
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nh->flow_lbl[0] = (nh->flow_lbl[0] & 0x0F) | ((tc & 0x0F) << 4);
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}
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static void set_ipv6_fl(struct ipv6hdr *nh, u32 fl)
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{
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nh->flow_lbl[0] = (nh->flow_lbl[0] & 0xF0) | (fl & 0x000F0000) >> 16;
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nh->flow_lbl[1] = (fl & 0x0000FF00) >> 8;
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nh->flow_lbl[2] = fl & 0x000000FF;
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}
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static void set_ip_ttl(struct sk_buff *skb, struct iphdr *nh, u8 new_ttl)
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{
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csum_replace2(&nh->check, htons(nh->ttl << 8), htons(new_ttl << 8));
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nh->ttl = new_ttl;
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}
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static int set_ipv4(struct sk_buff *skb, const struct ovs_key_ipv4 *ipv4_key)
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{
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struct iphdr *nh;
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int err;
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err = make_writable(skb, skb_network_offset(skb) +
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sizeof(struct iphdr));
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if (unlikely(err))
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return err;
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nh = ip_hdr(skb);
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if (ipv4_key->ipv4_src != nh->saddr)
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set_ip_addr(skb, nh, &nh->saddr, ipv4_key->ipv4_src);
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if (ipv4_key->ipv4_dst != nh->daddr)
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set_ip_addr(skb, nh, &nh->daddr, ipv4_key->ipv4_dst);
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if (ipv4_key->ipv4_tos != nh->tos)
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ipv4_change_dsfield(nh, 0, ipv4_key->ipv4_tos);
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if (ipv4_key->ipv4_ttl != nh->ttl)
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set_ip_ttl(skb, nh, ipv4_key->ipv4_ttl);
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return 0;
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}
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static int set_ipv6(struct sk_buff *skb, const struct ovs_key_ipv6 *ipv6_key)
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{
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struct ipv6hdr *nh;
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int err;
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__be32 *saddr;
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__be32 *daddr;
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err = make_writable(skb, skb_network_offset(skb) +
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sizeof(struct ipv6hdr));
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if (unlikely(err))
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return err;
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nh = ipv6_hdr(skb);
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saddr = (__be32 *)&nh->saddr;
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daddr = (__be32 *)&nh->daddr;
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if (memcmp(ipv6_key->ipv6_src, saddr, sizeof(ipv6_key->ipv6_src)))
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set_ipv6_addr(skb, ipv6_key->ipv6_proto, saddr,
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ipv6_key->ipv6_src, true);
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if (memcmp(ipv6_key->ipv6_dst, daddr, sizeof(ipv6_key->ipv6_dst))) {
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unsigned int offset = 0;
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int flags = IP6_FH_F_SKIP_RH;
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bool recalc_csum = true;
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if (ipv6_ext_hdr(nh->nexthdr))
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recalc_csum = ipv6_find_hdr(skb, &offset,
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NEXTHDR_ROUTING, NULL,
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&flags) != NEXTHDR_ROUTING;
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set_ipv6_addr(skb, ipv6_key->ipv6_proto, daddr,
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ipv6_key->ipv6_dst, recalc_csum);
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}
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set_ipv6_tc(nh, ipv6_key->ipv6_tclass);
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set_ipv6_fl(nh, ntohl(ipv6_key->ipv6_label));
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nh->hop_limit = ipv6_key->ipv6_hlimit;
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return 0;
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}
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/* Must follow make_writable() since that can move the skb data. */
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static void set_tp_port(struct sk_buff *skb, __be16 *port,
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__be16 new_port, __sum16 *check)
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{
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inet_proto_csum_replace2(check, skb, *port, new_port, 0);
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*port = new_port;
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skb->rxhash = 0;
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}
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static void set_udp_port(struct sk_buff *skb, __be16 *port, __be16 new_port)
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{
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struct udphdr *uh = udp_hdr(skb);
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if (uh->check && skb->ip_summed != CHECKSUM_PARTIAL) {
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set_tp_port(skb, port, new_port, &uh->check);
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if (!uh->check)
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uh->check = CSUM_MANGLED_0;
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} else {
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*port = new_port;
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skb->rxhash = 0;
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}
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}
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static int set_udp(struct sk_buff *skb, const struct ovs_key_udp *udp_port_key)
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{
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struct udphdr *uh;
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int err;
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err = make_writable(skb, skb_transport_offset(skb) +
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sizeof(struct udphdr));
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if (unlikely(err))
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return err;
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uh = udp_hdr(skb);
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if (udp_port_key->udp_src != uh->source)
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set_udp_port(skb, &uh->source, udp_port_key->udp_src);
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if (udp_port_key->udp_dst != uh->dest)
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set_udp_port(skb, &uh->dest, udp_port_key->udp_dst);
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return 0;
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}
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static int set_tcp(struct sk_buff *skb, const struct ovs_key_tcp *tcp_port_key)
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{
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struct tcphdr *th;
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int err;
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err = make_writable(skb, skb_transport_offset(skb) +
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sizeof(struct tcphdr));
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if (unlikely(err))
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return err;
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th = tcp_hdr(skb);
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if (tcp_port_key->tcp_src != th->source)
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set_tp_port(skb, &th->source, tcp_port_key->tcp_src, &th->check);
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if (tcp_port_key->tcp_dst != th->dest)
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set_tp_port(skb, &th->dest, tcp_port_key->tcp_dst, &th->check);
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return 0;
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}
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static int do_output(struct datapath *dp, struct sk_buff *skb, int out_port)
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{
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struct vport *vport;
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if (unlikely(!skb))
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return -ENOMEM;
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vport = ovs_vport_rcu(dp, out_port);
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if (unlikely(!vport)) {
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kfree_skb(skb);
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return -ENODEV;
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}
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ovs_vport_send(vport, skb);
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return 0;
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}
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static int output_userspace(struct datapath *dp, struct sk_buff *skb,
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const struct nlattr *attr)
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{
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struct dp_upcall_info upcall;
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const struct nlattr *a;
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int rem;
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upcall.cmd = OVS_PACKET_CMD_ACTION;
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upcall.key = &OVS_CB(skb)->flow->key;
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upcall.userdata = NULL;
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upcall.portid = 0;
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for (a = nla_data(attr), rem = nla_len(attr); rem > 0;
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a = nla_next(a, &rem)) {
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switch (nla_type(a)) {
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case OVS_USERSPACE_ATTR_USERDATA:
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upcall.userdata = a;
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break;
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case OVS_USERSPACE_ATTR_PID:
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upcall.portid = nla_get_u32(a);
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break;
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}
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}
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return ovs_dp_upcall(dp, skb, &upcall);
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}
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static int sample(struct datapath *dp, struct sk_buff *skb,
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const struct nlattr *attr)
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{
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const struct nlattr *acts_list = NULL;
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const struct nlattr *a;
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int rem;
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for (a = nla_data(attr), rem = nla_len(attr); rem > 0;
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a = nla_next(a, &rem)) {
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switch (nla_type(a)) {
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case OVS_SAMPLE_ATTR_PROBABILITY:
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if (net_random() >= nla_get_u32(a))
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return 0;
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break;
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case OVS_SAMPLE_ATTR_ACTIONS:
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acts_list = a;
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break;
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}
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}
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return do_execute_actions(dp, skb, nla_data(acts_list),
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nla_len(acts_list), true);
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}
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static int execute_set_action(struct sk_buff *skb,
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const struct nlattr *nested_attr)
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{
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int err = 0;
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switch (nla_type(nested_attr)) {
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case OVS_KEY_ATTR_PRIORITY:
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skb->priority = nla_get_u32(nested_attr);
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break;
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case OVS_KEY_ATTR_SKB_MARK:
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skb->mark = nla_get_u32(nested_attr);
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break;
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case OVS_KEY_ATTR_ETHERNET:
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err = set_eth_addr(skb, nla_data(nested_attr));
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break;
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case OVS_KEY_ATTR_IPV4:
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err = set_ipv4(skb, nla_data(nested_attr));
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break;
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case OVS_KEY_ATTR_IPV6:
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err = set_ipv6(skb, nla_data(nested_attr));
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break;
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case OVS_KEY_ATTR_TCP:
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err = set_tcp(skb, nla_data(nested_attr));
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break;
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case OVS_KEY_ATTR_UDP:
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err = set_udp(skb, nla_data(nested_attr));
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break;
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}
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return err;
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}
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/* Execute a list of actions against 'skb'. */
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static int do_execute_actions(struct datapath *dp, struct sk_buff *skb,
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const struct nlattr *attr, int len, bool keep_skb)
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{
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/* Every output action needs a separate clone of 'skb', but the common
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* case is just a single output action, so that doing a clone and
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* then freeing the original skbuff is wasteful. So the following code
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* is slightly obscure just to avoid that. */
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int prev_port = -1;
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const struct nlattr *a;
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|
int rem;
|
|
|
|
for (a = attr, rem = len; rem > 0;
|
|
a = nla_next(a, &rem)) {
|
|
int err = 0;
|
|
|
|
if (prev_port != -1) {
|
|
do_output(dp, skb_clone(skb, GFP_ATOMIC), prev_port);
|
|
prev_port = -1;
|
|
}
|
|
|
|
switch (nla_type(a)) {
|
|
case OVS_ACTION_ATTR_OUTPUT:
|
|
prev_port = nla_get_u32(a);
|
|
break;
|
|
|
|
case OVS_ACTION_ATTR_USERSPACE:
|
|
output_userspace(dp, skb, a);
|
|
break;
|
|
|
|
case OVS_ACTION_ATTR_PUSH_VLAN:
|
|
err = push_vlan(skb, nla_data(a));
|
|
if (unlikely(err)) /* skb already freed. */
|
|
return err;
|
|
break;
|
|
|
|
case OVS_ACTION_ATTR_POP_VLAN:
|
|
err = pop_vlan(skb);
|
|
break;
|
|
|
|
case OVS_ACTION_ATTR_SET:
|
|
err = execute_set_action(skb, nla_data(a));
|
|
break;
|
|
|
|
case OVS_ACTION_ATTR_SAMPLE:
|
|
err = sample(dp, skb, a);
|
|
break;
|
|
}
|
|
|
|
if (unlikely(err)) {
|
|
kfree_skb(skb);
|
|
return err;
|
|
}
|
|
}
|
|
|
|
if (prev_port != -1) {
|
|
if (keep_skb)
|
|
skb = skb_clone(skb, GFP_ATOMIC);
|
|
|
|
do_output(dp, skb, prev_port);
|
|
} else if (!keep_skb)
|
|
consume_skb(skb);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/* Execute a list of actions against 'skb'. */
|
|
int ovs_execute_actions(struct datapath *dp, struct sk_buff *skb)
|
|
{
|
|
struct sw_flow_actions *acts = rcu_dereference(OVS_CB(skb)->flow->sf_acts);
|
|
|
|
return do_execute_actions(dp, skb, acts->actions,
|
|
acts->actions_len, false);
|
|
}
|