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Message-Id: <1425888098-21875-4-git-send-email-azhou@nicira.com>
Date: Mon, 9 Mar 2015 01:01:37 -0700
From: Andy Zhou <azhou@...ira.com>
To: davem@...emloft.net
Cc: netdev@...r.kernel.org, Andy Zhou <azhou@...ira.com>
Subject: [patch net-next 3/4] net: refactor IPv4 and IPv6 fragmentation APIs
Both ip_fragment() and ip6_fragment() APIs assume skb has an
attached netdev device, from which the MTU size can be derived.
However, skbs incoming from OVS vports do not have an attached
netdev device.
This patch splits the original function into two parts: The core
fragmentation logic is now provided by
ip_fragment_mtu()/ip6_fragment_mut().
The original APIs are kept as is. Their implementation now calls
the new APIs. Any information derived from the attached netdev
device is first derived in the original APIs and passed into the
new APIs.
In addition, The call back output function into the new APIs now
accepts two arguments: a skb and an application specific pointer,
which specifies additional information not directly associated
with skb, such as OVS flow, to the output function.
Signed-off-by: Andy Zhou <azhou@...ira.com>
---
include/net/ip.h | 3 +
include/net/ipv6.h | 4 ++
net/ipv4/ip_output.c | 113 ++++++++++++++++++++----------------
net/ipv6/ip6_output.c | 157 ++++++++++++++++++++++++++++++--------------------
4 files changed, 166 insertions(+), 111 deletions(-)
diff --git a/include/net/ip.h b/include/net/ip.h
index 025c61c..e73ac20 100644
--- a/include/net/ip.h
+++ b/include/net/ip.h
@@ -109,6 +109,9 @@ int ip_mr_input(struct sk_buff *skb);
int ip_output(struct sock *sk, struct sk_buff *skb);
int ip_mc_output(struct sock *sk, struct sk_buff *skb);
int ip_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *));
+int ip_fragment_mtu(struct sk_buff *skb, unsigned int mtu, unsigned int ll_rs,
+ struct net_device *dev, void *output_arg,
+ int (*output)(struct sk_buff *, void *output_arg));
int ip_do_nat(struct sk_buff *skb);
void ip_send_check(struct iphdr *ip);
int __ip_local_out(struct sk_buff *skb);
diff --git a/include/net/ipv6.h b/include/net/ipv6.h
index 780c098..e51c6c6 100644
--- a/include/net/ipv6.h
+++ b/include/net/ipv6.h
@@ -910,6 +910,10 @@ int ip6_mc_source(int add, int omode, struct sock *sk,
int ip6_mc_msfilter(struct sock *sk, struct group_filter *gsf);
int ip6_mc_msfget(struct sock *sk, struct group_filter *gsf,
struct group_filter __user *optval, int __user *optlen);
+int ip6_fragment_mtu(struct sk_buff *skb, unsigned int mtu, int hroom,
+ int troom, struct net_device *dev, __be32 frag_id,
+ void *output_arg,
+ int (*output)(struct sk_buff *, void *));
#ifdef CONFIG_PROC_FS
int ac6_proc_init(struct net *net);
diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
index a7aea20..b85fd34 100644
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c
@@ -472,54 +472,22 @@ static void ip_copy_metadata(struct sk_buff *to, struct sk_buff *from)
skb_copy_secmark(to, from);
}
-/*
- * This IP datagram is too large to be sent in one piece. Break it up into
- * smaller pieces (each of size equal to IP header plus
- * a block of the data of the original IP data part) that will yet fit in a
- * single device frame, and queue such a frame for sending.
- */
-
-int ip_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *))
+int ip_fragment_mtu(struct sk_buff *skb, unsigned int mtu, unsigned int ll_rs,
+ struct net_device *dev, void *output_arg,
+ int (*output)(struct sk_buff *, void *output_arg))
{
struct iphdr *iph;
int ptr;
- struct net_device *dev;
struct sk_buff *skb2;
- unsigned int mtu, hlen, left, len, ll_rs;
+ unsigned int hlen, left, len;
int offset;
__be16 not_last_frag;
- struct rtable *rt = skb_rtable(skb);
int err = 0;
- dev = rt->dst.dev;
-
- /*
- * Point into the IP datagram header.
- */
-
iph = ip_hdr(skb);
-
- mtu = ip_skb_dst_mtu(skb);
- if (unlikely(((iph->frag_off & htons(IP_DF)) && !skb->ignore_df) ||
- (IPCB(skb)->frag_max_size &&
- IPCB(skb)->frag_max_size > mtu))) {
- IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGFAILS);
- icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED,
- htonl(mtu));
- kfree_skb(skb);
- return -EMSGSIZE;
- }
-
- /*
- * Setup starting values.
- */
-
hlen = iph->ihl * 4;
mtu = mtu - hlen; /* Size of data space */
-#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
- if (skb->nf_bridge)
- mtu -= nf_bridge_mtu_reduction(skb);
-#endif
+
IPCB(skb)->flags |= IPSKB_FRAG_COMPLETE;
/* When frag_list is given, use it. First, check its validity:
@@ -592,10 +560,11 @@ int ip_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *))
ip_send_check(iph);
}
- err = output(skb);
+ err = output(skb, output_arg);
- if (!err)
- IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGCREATES);
+ if (!err && dev)
+ IP_INC_STATS(dev_net(dev),
+ IPSTATS_MIB_FRAGCREATES);
if (err || !frag)
break;
@@ -605,7 +574,8 @@ int ip_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *))
}
if (err == 0) {
- IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGOKS);
+ if (dev)
+ IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGOKS);
return 0;
}
@@ -614,7 +584,8 @@ int ip_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *))
kfree_skb(frag);
frag = skb;
}
- IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGFAILS);
+ if (dev)
+ IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGFAILS);
return err;
slow_path_clean:
@@ -636,10 +607,6 @@ slow_path:
left = skb->len - hlen; /* Space per frame */
ptr = hlen; /* Where to start from */
- /* for bridged IP traffic encapsulated inside f.e. a vlan header,
- * we need to make room for the encapsulating header
- */
- ll_rs = LL_RESERVED_SPACE_EXTRA(rt->dst.dev, nf_bridge_pad(skb));
/*
* Fragment the datagram.
@@ -732,21 +699,67 @@ slow_path:
ip_send_check(iph);
- err = output(skb2);
+ err = output(skb2, output_arg);
if (err)
goto fail;
- IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGCREATES);
+ if (dev)
+ IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGCREATES);
}
consume_skb(skb);
- IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGOKS);
+ if (dev)
+ IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGOKS);
return err;
fail:
kfree_skb(skb);
- IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGFAILS);
+ if (dev)
+ IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGFAILS);
return err;
}
+EXPORT_SYMBOL(ip_fragment_mtu);
+
+/*This IP datagram is too large to be sent in one piece. Break it up into
+ *smaller pieces (each of size equal to IP header plus
+ *a block of the data of the original IP data part) that will yet fit in a
+ *single device frame, and queue such a frame for sending.
+ */
+int ip_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *))
+{
+ struct iphdr *iph;
+ struct net_device *dev;
+ unsigned int mtu, ll_rs;
+ struct rtable *rt = skb_rtable(skb);
+
+ dev = rt->dst.dev;
+
+ /* Point into the IP datagram header. */
+ iph = ip_hdr(skb);
+
+ mtu = ip_skb_dst_mtu(skb);
+ if (unlikely(((iph->frag_off & htons(IP_DF)) && !skb->ignore_df) ||
+ (IPCB(skb)->frag_max_size &&
+ IPCB(skb)->frag_max_size > mtu))) {
+ IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGFAILS);
+ icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED,
+ htonl(mtu));
+ kfree_skb(skb);
+ return -EMSGSIZE;
+ }
+
+ /* Setup starting values. */
+#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
+ if (skb->nf_bridge)
+ mtu -= nf_bridge_mtu_reduction(skb);
+#endif
+ /* for bridged IP traffic encapsulated inside f.e. a vlan header,
+ * we need to make room for the encapsulating header
+ */
+ ll_rs = LL_RESERVED_SPACE_EXTRA(rt->dst.dev, nf_bridge_pad(skb));
+
+ return ip_fragment_mtu(skb, mtu, ll_rs, NULL, dev,
+ (int (*)(struct sk_buff *, void *output_arg))output);
+}
EXPORT_SYMBOL(ip_fragment);
int
diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index 0a04a37..378054c 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -537,46 +537,33 @@ static void ip6_copy_metadata(struct sk_buff *to, struct sk_buff *from)
skb_copy_secmark(to, from);
}
-int ip6_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *))
+int ip6_fragment_mtu(struct sk_buff *skb, unsigned int mtu,
+ int hroom, int troom, struct net_device *dev,
+ __be32 frag_id, void *output_arg,
+ int (*output)(struct sk_buff *, void *output_arg))
{
struct sk_buff *frag;
- struct rt6_info *rt = (struct rt6_info *)skb_dst(skb);
- struct ipv6_pinfo *np = skb->sk ? inet6_sk(skb->sk) : NULL;
+ struct rt6_info *rt;
+ struct net *net;
struct ipv6hdr *tmp_hdr;
struct frag_hdr *fh;
- unsigned int mtu, hlen, left, len;
- int hroom, troom;
- __be32 frag_id = 0;
- int ptr, offset = 0, err = 0;
+ unsigned int hlen, left, len;
u8 *prevhdr, nexthdr = 0;
- struct net *net = dev_net(skb_dst(skb)->dev);
-
- hlen = ip6_find_1stfragopt(skb, &prevhdr);
- nexthdr = *prevhdr;
-
- mtu = ip6_skb_dst_mtu(skb);
-
- /* We must not fragment if the socket is set to force MTU discovery
- * or if the skb it not generated by a local socket.
- */
- if (unlikely(!skb->ignore_df && skb->len > mtu) ||
- (IP6CB(skb)->frag_max_size &&
- IP6CB(skb)->frag_max_size > mtu)) {
- if (skb->sk && dst_allfrag(skb_dst(skb)))
- sk_nocaps_add(skb->sk, NETIF_F_GSO_MASK);
+ int ptr, offset = 0, err = 0;
- skb->dev = skb_dst(skb)->dev;
- icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
- IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
- IPSTATS_MIB_FRAGFAILS);
- kfree_skb(skb);
- return -EMSGSIZE;
+ if (dev) {
+ net = dev_net(skb_dst(skb)->dev);
+ rt = (struct rt6_info *)skb_dst(skb);
+ } else {
+ net = NULL;
+ rt = NULL;
}
- if (np && np->frag_size < mtu) {
- if (np->frag_size)
- mtu = np->frag_size;
- }
+ if (!frag_id)
+ frag_id = htonl(1);
+
+ hlen = ip6_find_1stfragopt(skb, &prevhdr);
+ nexthdr = *prevhdr;
mtu -= hlen + sizeof(struct frag_hdr);
if (skb_has_frag_list(skb)) {
@@ -616,8 +603,9 @@ int ip6_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *))
*prevhdr = NEXTHDR_FRAGMENT;
tmp_hdr = kmemdup(skb_network_header(skb), hlen, GFP_ATOMIC);
if (!tmp_hdr) {
- IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
- IPSTATS_MIB_FRAGFAILS);
+ if (dev)
+ IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
+ IPSTATS_MIB_FRAGFAILS);
return -ENOMEM;
}
@@ -627,11 +615,10 @@ int ip6_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *))
skb_reset_network_header(skb);
memcpy(skb_network_header(skb), tmp_hdr, hlen);
- ipv6_select_ident(fh, rt);
fh->nexthdr = nexthdr;
fh->reserved = 0;
fh->frag_off = htons(IP6_MF);
- frag_id = fh->identification;
+ fh->identification = frag_id;
first_len = skb_pagelen(skb);
skb->data_len = first_len - skb_headlen(skb);
@@ -639,7 +626,8 @@ int ip6_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *))
ipv6_hdr(skb)->payload_len = htons(first_len -
sizeof(struct ipv6hdr));
- dst_hold(&rt->dst);
+ if (dev)
+ dst_hold(&rt->dst);
for (;;) {
/* Prepare header of the next frame,
@@ -665,8 +653,8 @@ int ip6_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *))
ip6_copy_metadata(frag, skb);
}
- err = output(skb);
- if (!err)
+ err = output(skb, output_arg);
+ if (!err && dev)
IP6_INC_STATS(net, ip6_dst_idev(&rt->dst),
IPSTATS_MIB_FRAGCREATES);
@@ -681,17 +669,21 @@ int ip6_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *))
kfree(tmp_hdr);
if (err == 0) {
- IP6_INC_STATS(net, ip6_dst_idev(&rt->dst),
- IPSTATS_MIB_FRAGOKS);
- ip6_rt_put(rt);
+ if (dev) {
+ IP6_INC_STATS(net, ip6_dst_idev(&rt->dst),
+ IPSTATS_MIB_FRAGOKS);
+ ip6_rt_put(rt);
+ }
return 0;
}
kfree_skb_list(frag);
- IP6_INC_STATS(net, ip6_dst_idev(&rt->dst),
- IPSTATS_MIB_FRAGFAILS);
- ip6_rt_put(rt);
+ if (dev) {
+ IP6_INC_STATS(net, ip6_dst_idev(&rt->dst),
+ IPSTATS_MIB_FRAGFAILS);
+ ip6_rt_put(rt);
+ }
return err;
slow_path_clean:
@@ -717,8 +709,6 @@ slow_path:
*/
*prevhdr = NEXTHDR_FRAGMENT;
- hroom = LL_RESERVED_SPACE(rt->dst.dev);
- troom = rt->dst.dev->needed_tailroom;
/*
* Keep copying data until we run out.
@@ -738,8 +728,10 @@ slow_path:
frag = alloc_skb(len + hlen + sizeof(struct frag_hdr) +
hroom + troom, GFP_ATOMIC);
if (!frag) {
- IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
- IPSTATS_MIB_FRAGFAILS);
+ if (dev)
+ IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
+ IPSTATS_MIB_FRAGFAILS);
+
err = -ENOMEM;
goto fail;
}
@@ -773,11 +765,7 @@ slow_path:
*/
fh->nexthdr = nexthdr;
fh->reserved = 0;
- if (!frag_id) {
- ipv6_select_ident(fh, rt);
- frag_id = fh->identification;
- } else
- fh->identification = frag_id;
+ fh->identification = frag_id;
/*
* Copy a block of the IP datagram.
@@ -798,24 +786,71 @@ slow_path:
/*
* Put this fragment into the sending queue.
*/
- err = output(frag);
+ err = output(frag, output_arg);
if (err)
goto fail;
- IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
- IPSTATS_MIB_FRAGCREATES);
+ if (dev)
+ IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
+ IPSTATS_MIB_FRAGCREATES);
}
- IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
- IPSTATS_MIB_FRAGOKS);
+ if (dev)
+ IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
+ IPSTATS_MIB_FRAGOKS);
consume_skb(skb);
return err;
fail:
- IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
- IPSTATS_MIB_FRAGFAILS);
+ if (dev)
+ IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
+ IPSTATS_MIB_FRAGFAILS);
kfree_skb(skb);
return err;
}
+EXPORT_SYMBOL(ip6_fragment_mtu);
+
+int ip6_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *))
+{
+ struct ipv6_pinfo *np = skb->sk ? inet6_sk(skb->sk) : NULL;
+ struct rt6_info *rt = (struct rt6_info *)skb_dst(skb);
+ struct net_device *dev = skb_dst(skb)->dev;
+ struct net *net = dev_net(skb_dst(skb)->dev);
+ struct frag_hdr fh;
+ unsigned int mtu;
+ int hroom, troom;
+
+ hroom = LL_RESERVED_SPACE(rt->dst.dev);
+ troom = rt->dst.dev->needed_tailroom;
+ mtu = ip6_skb_dst_mtu(skb);
+
+ /* We must not fragment if the socket is set to force MTU discovery
+ * or if the skb it not generated by a local socket.
+ */
+ if (unlikely(!skb->ignore_df && skb->len > mtu) ||
+ (IP6CB(skb)->frag_max_size &&
+ IP6CB(skb)->frag_max_size > mtu)) {
+ if (skb->sk && dst_allfrag(skb_dst(skb)))
+ sk_nocaps_add(skb->sk, NETIF_F_GSO_MASK);
+
+ skb->dev = skb_dst(skb)->dev;
+ icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
+ IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
+ IPSTATS_MIB_FRAGFAILS);
+ kfree_skb(skb);
+ return -EMSGSIZE;
+ }
+
+ if (np && np->frag_size < mtu) {
+ if (np->frag_size)
+ mtu = np->frag_size;
+ }
+
+ dev = skb_dst(skb)->dev;
+ ipv6_select_ident(&fh, rt);
+ return ip6_fragment_mtu(skb, mtu, hroom, troom, dev,
+ fh.identification, NULL,
+ (int (*)(struct sk_buff *, void *)) output);
+}
static inline int ip6_rt_check(const struct rt6key *rt_key,
const struct in6_addr *fl_addr,
--
1.9.1
--
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