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-rw-r--r--target/linux/generic/backport-4.19/395-v5.8-net-sch_cake-Take-advantage-of-skb-hash-where-appropriate.patch6
-rw-r--r--target/linux/generic/backport-4.19/396-5.8-sch_cake-don-t-try-to-reallocate-or-unshare-skb-unco.patch96
-rw-r--r--target/linux/generic/backport-4.19/397-5.8-sch_cake-don-t-call-diffserv-parsing-code-when-it-is.patch62
-rw-r--r--target/linux/generic/backport-4.19/398-5.8-sch_cake-fix-a-few-style-nits.patch40
-rw-r--r--target/linux/generic/backport-4.19/399-5.9-sch_cake-add-RFC-8622-LE-PHB-support-to-CAKE-diffser.patch57
-rw-r--r--target/linux/generic/backport-5.4/393-v5.5-sch_cake-drop-unused-variable-tin_quantum_prio.patch16
-rw-r--r--target/linux/generic/backport-5.4/395-v5.8-net-sch_cake-Take-advantage-of-skb-hash-where-appropriate.patch6
-rw-r--r--target/linux/generic/backport-5.4/396-5.8-sch_cake-don-t-try-to-reallocate-or-unshare-skb-unco.patch96
-rw-r--r--target/linux/generic/backport-5.4/397-5.8-sch_cake-don-t-call-diffserv-parsing-code-when-it-is.patch62
-rw-r--r--target/linux/generic/backport-5.4/398-5.8-sch_cake-fix-a-few-style-nits.patch40
-rw-r--r--target/linux/generic/backport-5.4/399-5.9-sch_cake-add-RFC-8622-LE-PHB-support-to-CAKE-diffser.patch57
-rw-r--r--target/linux/generic/hack-4.19/641-sch_cake-fix-IP-protocol-handling-in-the-presence-of.patch114
-rw-r--r--target/linux/generic/hack-5.4/641-sch_cake-fix-IP-protocol-handling-in-the-presence-of.patch114
13 files changed, 752 insertions, 14 deletions
diff --git a/target/linux/generic/backport-4.19/395-v5.8-net-sch_cake-Take-advantage-of-skb-hash-where-appropriate.patch b/target/linux/generic/backport-4.19/395-v5.8-net-sch_cake-Take-advantage-of-skb-hash-where-appropriate.patch
index 7b3396c6c3..12962135d0 100644
--- a/target/linux/generic/backport-4.19/395-v5.8-net-sch_cake-Take-advantage-of-skb-hash-where-appropriate.patch
+++ b/target/linux/generic/backport-4.19/395-v5.8-net-sch_cake-Take-advantage-of-skb-hash-where-appropriate.patch
@@ -53,7 +53,7 @@ Signed-off-by: Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>
--- a/net/sched/sch_cake.c
+++ b/net/sched/sch_cake.c
-@@ -585,26 +585,48 @@ static bool cobalt_should_drop(struct co
+@@ -584,26 +584,48 @@ static bool cobalt_should_drop(struct co
return drop;
}
@@ -110,7 +110,7 @@ Signed-off-by: Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>
#endif
}
-@@ -625,23 +647,36 @@ static bool cake_ddst(int flow_mode)
+@@ -624,23 +646,36 @@ static bool cake_ddst(int flow_mode)
static u32 cake_hash(struct cake_tin_data *q, const struct sk_buff *skb,
int flow_mode, u16 flow_override, u16 host_override)
{
@@ -152,7 +152,7 @@ Signed-off-by: Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>
/* flow_hash_from_keys() sorts the addresses by value, so we have
* to preserve their order in a separate data structure to treat
-@@ -680,12 +715,14 @@ static u32 cake_hash(struct cake_tin_dat
+@@ -679,12 +714,14 @@ static u32 cake_hash(struct cake_tin_dat
/* This *must* be after the above switch, since as a
* side-effect it sorts the src and dst addresses.
*/
diff --git a/target/linux/generic/backport-4.19/396-5.8-sch_cake-don-t-try-to-reallocate-or-unshare-skb-unco.patch b/target/linux/generic/backport-4.19/396-5.8-sch_cake-don-t-try-to-reallocate-or-unshare-skb-unco.patch
new file mode 100644
index 0000000000..a36095c26c
--- /dev/null
+++ b/target/linux/generic/backport-4.19/396-5.8-sch_cake-don-t-try-to-reallocate-or-unshare-skb-unco.patch
@@ -0,0 +1,96 @@
+From 9208d2863ac689a563b92f2161d8d1e7127d0add Mon Sep 17 00:00:00 2001
+From: Ilya Ponetayev <i.ponetaev@ndmsystems.com>
+Date: Thu, 25 Jun 2020 22:12:07 +0200
+Subject: [PATCH] sch_cake: don't try to reallocate or unshare skb
+ unconditionally
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+cake_handle_diffserv() tries to linearize mac and network header parts of
+skb and to make it writable unconditionally. In some cases it leads to full
+skb reallocation, which reduces throughput and increases CPU load. Some
+measurements of IPv4 forward + NAPT on MIPS router with 580 MHz single-core
+CPU was conducted. It appears that on kernel 4.9 skb_try_make_writable()
+reallocates skb, if skb was allocated in ethernet driver via so-called
+'build skb' method from page cache (it was discovered by strange increase
+of kmalloc-2048 slab at first).
+
+Obtain DSCP value via read-only skb_header_pointer() call, and leave
+linearization only for DSCP bleaching or ECN CE setting. And, as an
+additional optimisation, skip diffserv parsing entirely if it is not needed
+by the current configuration.
+
+Fixes: c87b4ecdbe8d ("sch_cake: Make sure we can write the IP header before changing DSCP bits")
+Signed-off-by: Ilya Ponetayev <i.ponetaev@ndmsystems.com>
+[ fix a few style issues, reflow commit message ]
+Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
+Signed-off-by: David S. Miller <davem@davemloft.net>
+Signed-off-by: Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>
+---
+ net/sched/sch_cake.c | 41 ++++++++++++++++++++++++++++++-----------
+ 1 file changed, 30 insertions(+), 11 deletions(-)
+
+--- a/net/sched/sch_cake.c
++++ b/net/sched/sch_cake.c
+@@ -1553,30 +1553,49 @@ static unsigned int cake_drop(struct Qdi
+
+ static u8 cake_handle_diffserv(struct sk_buff *skb, u16 wash)
+ {
+- int wlen = skb_network_offset(skb);
++ const int offset = skb_network_offset(skb);
++ u16 *buf, buf_;
+ u8 dscp;
+
+ switch (tc_skb_protocol(skb)) {
+ case htons(ETH_P_IP):
+- wlen += sizeof(struct iphdr);
+- if (!pskb_may_pull(skb, wlen) ||
+- skb_try_make_writable(skb, wlen))
++ buf = skb_header_pointer(skb, offset, sizeof(buf_), &buf_);
++ if (unlikely(!buf))
+ return 0;
+
+- dscp = ipv4_get_dsfield(ip_hdr(skb)) >> 2;
+- if (wash && dscp)
++ /* ToS is in the second byte of iphdr */
++ dscp = ipv4_get_dsfield((struct iphdr *)buf) >> 2;
++
++ if (wash && dscp) {
++ const int wlen = offset + sizeof(struct iphdr);
++
++ if (!pskb_may_pull(skb, wlen) ||
++ skb_try_make_writable(skb, wlen))
++ return 0;
++
+ ipv4_change_dsfield(ip_hdr(skb), INET_ECN_MASK, 0);
++ }
++
+ return dscp;
+
+ case htons(ETH_P_IPV6):
+- wlen += sizeof(struct ipv6hdr);
+- if (!pskb_may_pull(skb, wlen) ||
+- skb_try_make_writable(skb, wlen))
++ buf = skb_header_pointer(skb, offset, sizeof(buf_), &buf_);
++ if (unlikely(!buf))
+ return 0;
+
+- dscp = ipv6_get_dsfield(ipv6_hdr(skb)) >> 2;
+- if (wash && dscp)
++ /* Traffic class is in the first and second bytes of ipv6hdr */
++ dscp = ipv6_get_dsfield((struct ipv6hdr *)buf) >> 2;
++
++ if (wash && dscp) {
++ const int wlen = offset + sizeof(struct ipv6hdr);
++
++ if (!pskb_may_pull(skb, wlen) ||
++ skb_try_make_writable(skb, wlen))
++ return 0;
++
+ ipv6_change_dsfield(ipv6_hdr(skb), INET_ECN_MASK, 0);
++ }
++
+ return dscp;
+
+ case htons(ETH_P_ARP):
diff --git a/target/linux/generic/backport-4.19/397-5.8-sch_cake-don-t-call-diffserv-parsing-code-when-it-is.patch b/target/linux/generic/backport-4.19/397-5.8-sch_cake-don-t-call-diffserv-parsing-code-when-it-is.patch
new file mode 100644
index 0000000000..b40bb36c74
--- /dev/null
+++ b/target/linux/generic/backport-4.19/397-5.8-sch_cake-don-t-call-diffserv-parsing-code-when-it-is.patch
@@ -0,0 +1,62 @@
+From 8c95eca0bb8c4bd2231a0d581f1ad0d50c90488c Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= <toke@redhat.com>
+Date: Thu, 25 Jun 2020 22:12:08 +0200
+Subject: [PATCH] sch_cake: don't call diffserv parsing code when it is not
+ needed
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+As a further optimisation of the diffserv parsing codepath, we can skip it
+entirely if CAKE is configured to neither use diffserv-based
+classification, nor to zero out the diffserv bits.
+
+Fixes: c87b4ecdbe8d ("sch_cake: Make sure we can write the IP header before changing DSCP bits")
+Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
+Signed-off-by: David S. Miller <davem@davemloft.net>
+Signed-off-by: Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>
+---
+ net/sched/sch_cake.c | 13 +++++++++----
+ 1 file changed, 9 insertions(+), 4 deletions(-)
+
+--- a/net/sched/sch_cake.c
++++ b/net/sched/sch_cake.c
+@@ -1551,7 +1551,7 @@ static unsigned int cake_drop(struct Qdi
+ return idx + (tin << 16);
+ }
+
+-static u8 cake_handle_diffserv(struct sk_buff *skb, u16 wash)
++static u8 cake_handle_diffserv(struct sk_buff *skb, bool wash)
+ {
+ const int offset = skb_network_offset(skb);
+ u16 *buf, buf_;
+@@ -1612,14 +1612,17 @@ static struct cake_tin_data *cake_select
+ {
+ struct cake_sched_data *q = qdisc_priv(sch);
+ u32 tin, mark;
++ bool wash;
+ u8 dscp;
+
+ /* Tin selection: Default to diffserv-based selection, allow overriding
+- * using firewall marks or skb->priority.
++ * using firewall marks or skb->priority. Call DSCP parsing early if
++ * wash is enabled, otherwise defer to below to skip unneeded parsing.
+ */
+- dscp = cake_handle_diffserv(skb,
+- q->rate_flags & CAKE_FLAG_WASH);
+ mark = (skb->mark & q->fwmark_mask) >> q->fwmark_shft;
++ wash = !!(q->rate_flags & CAKE_FLAG_WASH);
++ if (wash)
++ dscp = cake_handle_diffserv(skb, wash);
+
+ if (q->tin_mode == CAKE_DIFFSERV_BESTEFFORT)
+ tin = 0;
+@@ -1630,6 +1633,8 @@ static struct cake_tin_data *cake_select
+ tin = q->tin_order[TC_H_MIN(skb->priority) - 1];
+
+ else {
++ if (!wash)
++ dscp = cake_handle_diffserv(skb, wash);
+ tin = q->tin_index[dscp];
+
+ if (unlikely(tin >= q->tin_cnt))
diff --git a/target/linux/generic/backport-4.19/398-5.8-sch_cake-fix-a-few-style-nits.patch b/target/linux/generic/backport-4.19/398-5.8-sch_cake-fix-a-few-style-nits.patch
new file mode 100644
index 0000000000..a1d72113b7
--- /dev/null
+++ b/target/linux/generic/backport-4.19/398-5.8-sch_cake-fix-a-few-style-nits.patch
@@ -0,0 +1,40 @@
+From 3f608f0c41360b11b04c763f348b712f651c8bac Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= <toke@redhat.com>
+Date: Thu, 25 Jun 2020 22:12:09 +0200
+Subject: [PATCH] sch_cake: fix a few style nits
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+I spotted a few nits when comparing the in-tree version of sch_cake with
+the out-of-tree one: A redundant error variable declaration shadowing an
+outer declaration, and an indentation alignment issue. Fix both of these.
+
+Fixes: 046f6fd5daef ("sched: Add Common Applications Kept Enhanced (cake) qdisc")
+Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
+Signed-off-by: David S. Miller <davem@davemloft.net>
+Signed-off-by: Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>
+---
+ net/sched/sch_cake.c | 4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+--- a/net/sched/sch_cake.c
++++ b/net/sched/sch_cake.c
+@@ -2713,7 +2713,7 @@ static int cake_init(struct Qdisc *sch,
+ qdisc_watchdog_init(&q->watchdog, sch);
+
+ if (opt) {
+- int err = cake_change(sch, opt, extack);
++ err = cake_change(sch, opt, extack);
+
+ if (err)
+ return err;
+@@ -3030,7 +3030,7 @@ static int cake_dump_class_stats(struct
+ PUT_STAT_S32(BLUE_TIMER_US,
+ ktime_to_us(
+ ktime_sub(now,
+- flow->cvars.blue_timer)));
++ flow->cvars.blue_timer)));
+ }
+ if (flow->cvars.dropping) {
+ PUT_STAT_S32(DROP_NEXT_US,
diff --git a/target/linux/generic/backport-4.19/399-5.9-sch_cake-add-RFC-8622-LE-PHB-support-to-CAKE-diffser.patch b/target/linux/generic/backport-4.19/399-5.9-sch_cake-add-RFC-8622-LE-PHB-support-to-CAKE-diffser.patch
new file mode 100644
index 0000000000..e171b4cec7
--- /dev/null
+++ b/target/linux/generic/backport-4.19/399-5.9-sch_cake-add-RFC-8622-LE-PHB-support-to-CAKE-diffser.patch
@@ -0,0 +1,57 @@
+From b8392808eb3fc28e523e28cb258c81ca246deb9b Mon Sep 17 00:00:00 2001
+From: Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>
+Date: Thu, 25 Jun 2020 22:18:00 +0200
+Subject: [PATCH] sch_cake: add RFC 8622 LE PHB support to CAKE diffserv
+ handling
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+Change tin mapping on diffserv3, 4 & 8 for LE PHB support, in essence
+making LE a member of the Bulk tin.
+
+Bulk has the least priority and minimum of 1/16th total bandwidth in the
+face of higher priority traffic.
+
+NB: Diffserv 3 & 4 swap tin 0 & 1 priorities from the default order as
+found in diffserv8, in case anyone is wondering why it looks a bit odd.
+
+Signed-off-by: Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>
+[ reword commit message slightly ]
+Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
+Signed-off-by: David S. Miller <davem@davemloft.net>
+---
+ net/sched/sch_cake.c | 8 ++++----
+ 1 file changed, 4 insertions(+), 4 deletions(-)
+
+--- a/net/sched/sch_cake.c
++++ b/net/sched/sch_cake.c
+@@ -312,8 +312,8 @@ static const u8 precedence[] = {
+ };
+
+ static const u8 diffserv8[] = {
+- 2, 5, 1, 2, 4, 2, 2, 2,
+- 0, 2, 1, 2, 1, 2, 1, 2,
++ 2, 0, 1, 2, 4, 2, 2, 2,
++ 1, 2, 1, 2, 1, 2, 1, 2,
+ 5, 2, 4, 2, 4, 2, 4, 2,
+ 3, 2, 3, 2, 3, 2, 3, 2,
+ 6, 2, 3, 2, 3, 2, 3, 2,
+@@ -323,7 +323,7 @@ static const u8 diffserv8[] = {
+ };
+
+ static const u8 diffserv4[] = {
+- 0, 2, 0, 0, 2, 0, 0, 0,
++ 0, 1, 0, 0, 2, 0, 0, 0,
+ 1, 0, 0, 0, 0, 0, 0, 0,
+ 2, 0, 2, 0, 2, 0, 2, 0,
+ 2, 0, 2, 0, 2, 0, 2, 0,
+@@ -334,7 +334,7 @@ static const u8 diffserv4[] = {
+ };
+
+ static const u8 diffserv3[] = {
+- 0, 0, 0, 0, 2, 0, 0, 0,
++ 0, 1, 0, 0, 2, 0, 0, 0,
+ 1, 0, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0,
diff --git a/target/linux/generic/backport-5.4/393-v5.5-sch_cake-drop-unused-variable-tin_quantum_prio.patch b/target/linux/generic/backport-5.4/393-v5.5-sch_cake-drop-unused-variable-tin_quantum_prio.patch
index 33e5c54b8c..2be0d36392 100644
--- a/target/linux/generic/backport-5.4/393-v5.5-sch_cake-drop-unused-variable-tin_quantum_prio.patch
+++ b/target/linux/generic/backport-5.4/393-v5.5-sch_cake-drop-unused-variable-tin_quantum_prio.patch
@@ -32,7 +32,7 @@ Signed-off-by: David S. Miller <davem@davemloft.net>
s32 tin_deficit;
u32 tin_backlog;
u32 tin_dropped;
-@@ -1916,7 +1915,7 @@ begin:
+@@ -1919,7 +1918,7 @@ begin:
while (b->tin_deficit < 0 ||
!(b->sparse_flow_count + b->bulk_flow_count)) {
if (b->tin_deficit <= 0)
@@ -41,7 +41,7 @@ Signed-off-by: David S. Miller <davem@davemloft.net>
if (b->sparse_flow_count + b->bulk_flow_count)
empty = false;
-@@ -2237,8 +2236,7 @@ static int cake_config_besteffort(struct
+@@ -2241,8 +2240,7 @@ static int cake_config_besteffort(struct
cake_set_rate(b, rate, mtu,
us_to_ns(q->target), us_to_ns(q->interval));
@@ -51,7 +51,7 @@ Signed-off-by: David S. Miller <davem@davemloft.net>
return 0;
}
-@@ -2249,8 +2247,7 @@ static int cake_config_precedence(struct
+@@ -2253,8 +2251,7 @@ static int cake_config_precedence(struct
struct cake_sched_data *q = qdisc_priv(sch);
u32 mtu = psched_mtu(qdisc_dev(sch));
u64 rate = q->rate_bps;
@@ -61,7 +61,7 @@ Signed-off-by: David S. Miller <davem@davemloft.net>
u32 i;
q->tin_cnt = 8;
-@@ -2263,18 +2260,14 @@ static int cake_config_precedence(struct
+@@ -2267,18 +2264,14 @@ static int cake_config_precedence(struct
cake_set_rate(b, rate, mtu, us_to_ns(q->target),
us_to_ns(q->interval));
@@ -83,7 +83,7 @@ Signed-off-by: David S. Miller <davem@davemloft.net>
}
return 0;
-@@ -2343,8 +2336,7 @@ static int cake_config_diffserv8(struct
+@@ -2347,8 +2340,7 @@ static int cake_config_diffserv8(struct
struct cake_sched_data *q = qdisc_priv(sch);
u32 mtu = psched_mtu(qdisc_dev(sch));
u64 rate = q->rate_bps;
@@ -93,7 +93,7 @@ Signed-off-by: David S. Miller <davem@davemloft.net>
u32 i;
q->tin_cnt = 8;
-@@ -2360,18 +2352,14 @@ static int cake_config_diffserv8(struct
+@@ -2364,18 +2356,14 @@ static int cake_config_diffserv8(struct
cake_set_rate(b, rate, mtu, us_to_ns(q->target),
us_to_ns(q->interval));
@@ -115,7 +115,7 @@ Signed-off-by: David S. Miller <davem@davemloft.net>
}
return 0;
-@@ -2410,17 +2398,11 @@ static int cake_config_diffserv4(struct
+@@ -2414,17 +2402,11 @@ static int cake_config_diffserv4(struct
cake_set_rate(&q->tins[3], rate >> 2, mtu,
us_to_ns(q->target), us_to_ns(q->interval));
@@ -137,7 +137,7 @@ Signed-off-by: David S. Miller <davem@davemloft.net>
return 0;
}
-@@ -2451,15 +2433,10 @@ static int cake_config_diffserv3(struct
+@@ -2455,15 +2437,10 @@ static int cake_config_diffserv3(struct
cake_set_rate(&q->tins[2], rate >> 2, mtu,
us_to_ns(q->target), us_to_ns(q->interval));
diff --git a/target/linux/generic/backport-5.4/395-v5.8-net-sch_cake-Take-advantage-of-skb-hash-where-appropriate.patch b/target/linux/generic/backport-5.4/395-v5.8-net-sch_cake-Take-advantage-of-skb-hash-where-appropriate.patch
index 7b3396c6c3..12962135d0 100644
--- a/target/linux/generic/backport-5.4/395-v5.8-net-sch_cake-Take-advantage-of-skb-hash-where-appropriate.patch
+++ b/target/linux/generic/backport-5.4/395-v5.8-net-sch_cake-Take-advantage-of-skb-hash-where-appropriate.patch
@@ -53,7 +53,7 @@ Signed-off-by: Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>
--- a/net/sched/sch_cake.c
+++ b/net/sched/sch_cake.c
-@@ -585,26 +585,48 @@ static bool cobalt_should_drop(struct co
+@@ -584,26 +584,48 @@ static bool cobalt_should_drop(struct co
return drop;
}
@@ -110,7 +110,7 @@ Signed-off-by: Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>
#endif
}
-@@ -625,23 +647,36 @@ static bool cake_ddst(int flow_mode)
+@@ -624,23 +646,36 @@ static bool cake_ddst(int flow_mode)
static u32 cake_hash(struct cake_tin_data *q, const struct sk_buff *skb,
int flow_mode, u16 flow_override, u16 host_override)
{
@@ -152,7 +152,7 @@ Signed-off-by: Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>
/* flow_hash_from_keys() sorts the addresses by value, so we have
* to preserve their order in a separate data structure to treat
-@@ -680,12 +715,14 @@ static u32 cake_hash(struct cake_tin_dat
+@@ -679,12 +714,14 @@ static u32 cake_hash(struct cake_tin_dat
/* This *must* be after the above switch, since as a
* side-effect it sorts the src and dst addresses.
*/
diff --git a/target/linux/generic/backport-5.4/396-5.8-sch_cake-don-t-try-to-reallocate-or-unshare-skb-unco.patch b/target/linux/generic/backport-5.4/396-5.8-sch_cake-don-t-try-to-reallocate-or-unshare-skb-unco.patch
new file mode 100644
index 0000000000..a36095c26c
--- /dev/null
+++ b/target/linux/generic/backport-5.4/396-5.8-sch_cake-don-t-try-to-reallocate-or-unshare-skb-unco.patch
@@ -0,0 +1,96 @@
+From 9208d2863ac689a563b92f2161d8d1e7127d0add Mon Sep 17 00:00:00 2001
+From: Ilya Ponetayev <i.ponetaev@ndmsystems.com>
+Date: Thu, 25 Jun 2020 22:12:07 +0200
+Subject: [PATCH] sch_cake: don't try to reallocate or unshare skb
+ unconditionally
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+cake_handle_diffserv() tries to linearize mac and network header parts of
+skb and to make it writable unconditionally. In some cases it leads to full
+skb reallocation, which reduces throughput and increases CPU load. Some
+measurements of IPv4 forward + NAPT on MIPS router with 580 MHz single-core
+CPU was conducted. It appears that on kernel 4.9 skb_try_make_writable()
+reallocates skb, if skb was allocated in ethernet driver via so-called
+'build skb' method from page cache (it was discovered by strange increase
+of kmalloc-2048 slab at first).
+
+Obtain DSCP value via read-only skb_header_pointer() call, and leave
+linearization only for DSCP bleaching or ECN CE setting. And, as an
+additional optimisation, skip diffserv parsing entirely if it is not needed
+by the current configuration.
+
+Fixes: c87b4ecdbe8d ("sch_cake: Make sure we can write the IP header before changing DSCP bits")
+Signed-off-by: Ilya Ponetayev <i.ponetaev@ndmsystems.com>
+[ fix a few style issues, reflow commit message ]
+Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
+Signed-off-by: David S. Miller <davem@davemloft.net>
+Signed-off-by: Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>
+---
+ net/sched/sch_cake.c | 41 ++++++++++++++++++++++++++++++-----------
+ 1 file changed, 30 insertions(+), 11 deletions(-)
+
+--- a/net/sched/sch_cake.c
++++ b/net/sched/sch_cake.c
+@@ -1553,30 +1553,49 @@ static unsigned int cake_drop(struct Qdi
+
+ static u8 cake_handle_diffserv(struct sk_buff *skb, u16 wash)
+ {
+- int wlen = skb_network_offset(skb);
++ const int offset = skb_network_offset(skb);
++ u16 *buf, buf_;
+ u8 dscp;
+
+ switch (tc_skb_protocol(skb)) {
+ case htons(ETH_P_IP):
+- wlen += sizeof(struct iphdr);
+- if (!pskb_may_pull(skb, wlen) ||
+- skb_try_make_writable(skb, wlen))
++ buf = skb_header_pointer(skb, offset, sizeof(buf_), &buf_);
++ if (unlikely(!buf))
+ return 0;
+
+- dscp = ipv4_get_dsfield(ip_hdr(skb)) >> 2;
+- if (wash && dscp)
++ /* ToS is in the second byte of iphdr */
++ dscp = ipv4_get_dsfield((struct iphdr *)buf) >> 2;
++
++ if (wash && dscp) {
++ const int wlen = offset + sizeof(struct iphdr);
++
++ if (!pskb_may_pull(skb, wlen) ||
++ skb_try_make_writable(skb, wlen))
++ return 0;
++
+ ipv4_change_dsfield(ip_hdr(skb), INET_ECN_MASK, 0);
++ }
++
+ return dscp;
+
+ case htons(ETH_P_IPV6):
+- wlen += sizeof(struct ipv6hdr);
+- if (!pskb_may_pull(skb, wlen) ||
+- skb_try_make_writable(skb, wlen))
++ buf = skb_header_pointer(skb, offset, sizeof(buf_), &buf_);
++ if (unlikely(!buf))
+ return 0;
+
+- dscp = ipv6_get_dsfield(ipv6_hdr(skb)) >> 2;
+- if (wash && dscp)
++ /* Traffic class is in the first and second bytes of ipv6hdr */
++ dscp = ipv6_get_dsfield((struct ipv6hdr *)buf) >> 2;
++
++ if (wash && dscp) {
++ const int wlen = offset + sizeof(struct ipv6hdr);
++
++ if (!pskb_may_pull(skb, wlen) ||
++ skb_try_make_writable(skb, wlen))
++ return 0;
++
+ ipv6_change_dsfield(ipv6_hdr(skb), INET_ECN_MASK, 0);
++ }
++
+ return dscp;
+
+ case htons(ETH_P_ARP):
diff --git a/target/linux/generic/backport-5.4/397-5.8-sch_cake-don-t-call-diffserv-parsing-code-when-it-is.patch b/target/linux/generic/backport-5.4/397-5.8-sch_cake-don-t-call-diffserv-parsing-code-when-it-is.patch
new file mode 100644
index 0000000000..2d9cd29780
--- /dev/null
+++ b/target/linux/generic/backport-5.4/397-5.8-sch_cake-don-t-call-diffserv-parsing-code-when-it-is.patch
@@ -0,0 +1,62 @@
+From 8c95eca0bb8c4bd2231a0d581f1ad0d50c90488c Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= <toke@redhat.com>
+Date: Thu, 25 Jun 2020 22:12:08 +0200
+Subject: [PATCH] sch_cake: don't call diffserv parsing code when it is not
+ needed
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+As a further optimisation of the diffserv parsing codepath, we can skip it
+entirely if CAKE is configured to neither use diffserv-based
+classification, nor to zero out the diffserv bits.
+
+Fixes: c87b4ecdbe8d ("sch_cake: Make sure we can write the IP header before changing DSCP bits")
+Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
+Signed-off-by: David S. Miller <davem@davemloft.net>
+Signed-off-by: Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>
+---
+ net/sched/sch_cake.c | 13 +++++++++----
+ 1 file changed, 9 insertions(+), 4 deletions(-)
+
+--- a/net/sched/sch_cake.c
++++ b/net/sched/sch_cake.c
+@@ -1551,7 +1551,7 @@ static unsigned int cake_drop(struct Qdi
+ return idx + (tin << 16);
+ }
+
+-static u8 cake_handle_diffserv(struct sk_buff *skb, u16 wash)
++static u8 cake_handle_diffserv(struct sk_buff *skb, bool wash)
+ {
+ const int offset = skb_network_offset(skb);
+ u16 *buf, buf_;
+@@ -1612,14 +1612,17 @@ static struct cake_tin_data *cake_select
+ {
+ struct cake_sched_data *q = qdisc_priv(sch);
+ u32 tin, mark;
++ bool wash;
+ u8 dscp;
+
+ /* Tin selection: Default to diffserv-based selection, allow overriding
+- * using firewall marks or skb->priority.
++ * using firewall marks or skb->priority. Call DSCP parsing early if
++ * wash is enabled, otherwise defer to below to skip unneeded parsing.
+ */
+- dscp = cake_handle_diffserv(skb,
+- q->rate_flags & CAKE_FLAG_WASH);
+ mark = (skb->mark & q->fwmark_mask) >> q->fwmark_shft;
++ wash = !!(q->rate_flags & CAKE_FLAG_WASH);
++ if (wash)
++ dscp = cake_handle_diffserv(skb, wash);
+
+ if (q->tin_mode == CAKE_DIFFSERV_BESTEFFORT)
+ tin = 0;
+@@ -1633,6 +1636,8 @@ static struct cake_tin_data *cake_select
+ tin = q->tin_order[TC_H_MIN(skb->priority) - 1];
+
+ else {
++ if (!wash)
++ dscp = cake_handle_diffserv(skb, wash);
+ tin = q->tin_index[dscp];
+
+ if (unlikely(tin >= q->tin_cnt))
diff --git a/target/linux/generic/backport-5.4/398-5.8-sch_cake-fix-a-few-style-nits.patch b/target/linux/generic/backport-5.4/398-5.8-sch_cake-fix-a-few-style-nits.patch
new file mode 100644
index 0000000000..1160489efb
--- /dev/null
+++ b/target/linux/generic/backport-5.4/398-5.8-sch_cake-fix-a-few-style-nits.patch
@@ -0,0 +1,40 @@
+From 3f608f0c41360b11b04c763f348b712f651c8bac Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= <toke@redhat.com>
+Date: Thu, 25 Jun 2020 22:12:09 +0200
+Subject: [PATCH] sch_cake: fix a few style nits
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+I spotted a few nits when comparing the in-tree version of sch_cake with
+the out-of-tree one: A redundant error variable declaration shadowing an
+outer declaration, and an indentation alignment issue. Fix both of these.
+
+Fixes: 046f6fd5daef ("sched: Add Common Applications Kept Enhanced (cake) qdisc")
+Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
+Signed-off-by: David S. Miller <davem@davemloft.net>
+Signed-off-by: Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>
+---
+ net/sched/sch_cake.c | 4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+--- a/net/sched/sch_cake.c
++++ b/net/sched/sch_cake.c
+@@ -2717,7 +2717,7 @@ static int cake_init(struct Qdisc *sch,
+ qdisc_watchdog_init(&q->watchdog, sch);
+
+ if (opt) {
+- int err = cake_change(sch, opt, extack);
++ err = cake_change(sch, opt, extack);
+
+ if (err)
+ return err;
+@@ -3034,7 +3034,7 @@ static int cake_dump_class_stats(struct
+ PUT_STAT_S32(BLUE_TIMER_US,
+ ktime_to_us(
+ ktime_sub(now,
+- flow->cvars.blue_timer)));
++ flow->cvars.blue_timer)));
+ }
+ if (flow->cvars.dropping) {
+ PUT_STAT_S32(DROP_NEXT_US,
diff --git a/target/linux/generic/backport-5.4/399-5.9-sch_cake-add-RFC-8622-LE-PHB-support-to-CAKE-diffser.patch b/target/linux/generic/backport-5.4/399-5.9-sch_cake-add-RFC-8622-LE-PHB-support-to-CAKE-diffser.patch
new file mode 100644
index 0000000000..e171b4cec7
--- /dev/null
+++ b/target/linux/generic/backport-5.4/399-5.9-sch_cake-add-RFC-8622-LE-PHB-support-to-CAKE-diffser.patch
@@ -0,0 +1,57 @@
+From b8392808eb3fc28e523e28cb258c81ca246deb9b Mon Sep 17 00:00:00 2001
+From: Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>
+Date: Thu, 25 Jun 2020 22:18:00 +0200
+Subject: [PATCH] sch_cake: add RFC 8622 LE PHB support to CAKE diffserv
+ handling
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+Change tin mapping on diffserv3, 4 & 8 for LE PHB support, in essence
+making LE a member of the Bulk tin.
+
+Bulk has the least priority and minimum of 1/16th total bandwidth in the
+face of higher priority traffic.
+
+NB: Diffserv 3 & 4 swap tin 0 & 1 priorities from the default order as
+found in diffserv8, in case anyone is wondering why it looks a bit odd.
+
+Signed-off-by: Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>
+[ reword commit message slightly ]
+Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
+Signed-off-by: David S. Miller <davem@davemloft.net>
+---
+ net/sched/sch_cake.c | 8 ++++----
+ 1 file changed, 4 insertions(+), 4 deletions(-)
+
+--- a/net/sched/sch_cake.c
++++ b/net/sched/sch_cake.c
+@@ -312,8 +312,8 @@ static const u8 precedence[] = {
+ };
+
+ static const u8 diffserv8[] = {
+- 2, 5, 1, 2, 4, 2, 2, 2,
+- 0, 2, 1, 2, 1, 2, 1, 2,
++ 2, 0, 1, 2, 4, 2, 2, 2,
++ 1, 2, 1, 2, 1, 2, 1, 2,
+ 5, 2, 4, 2, 4, 2, 4, 2,
+ 3, 2, 3, 2, 3, 2, 3, 2,
+ 6, 2, 3, 2, 3, 2, 3, 2,
+@@ -323,7 +323,7 @@ static const u8 diffserv8[] = {
+ };
+
+ static const u8 diffserv4[] = {
+- 0, 2, 0, 0, 2, 0, 0, 0,
++ 0, 1, 0, 0, 2, 0, 0, 0,
+ 1, 0, 0, 0, 0, 0, 0, 0,
+ 2, 0, 2, 0, 2, 0, 2, 0,
+ 2, 0, 2, 0, 2, 0, 2, 0,
+@@ -334,7 +334,7 @@ static const u8 diffserv4[] = {
+ };
+
+ static const u8 diffserv3[] = {
+- 0, 0, 0, 0, 2, 0, 0, 0,
++ 0, 1, 0, 0, 2, 0, 0, 0,
+ 1, 0, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0,
diff --git a/target/linux/generic/hack-4.19/641-sch_cake-fix-IP-protocol-handling-in-the-presence-of.patch b/target/linux/generic/hack-4.19/641-sch_cake-fix-IP-protocol-handling-in-the-presence-of.patch
new file mode 100644
index 0000000000..e651743c1d
--- /dev/null
+++ b/target/linux/generic/hack-4.19/641-sch_cake-fix-IP-protocol-handling-in-the-presence-of.patch
@@ -0,0 +1,114 @@
+From a00590d570212c3c633bd463cef8ec7377cc7993 Mon Sep 17 00:00:00 2001
+From: Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>
+Date: Tue, 30 Jun 2020 12:07:44 +0100
+Subject: [PATCH] sch_cake: fix IP protocol handling in the presence of VLAN
+ tags
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+From: Ilya Ponetayev <i.ponetaev@ndmsystems.com>
+
+CAKE was using the return value of tc_skb_protocol() and expecting it to be
+the IP protocol type. This can fail in the presence of QinQ VLAN tags,
+making CAKE unable to handle ECN marking and diffserv parsing in this case.
+Fix this by implementing our own version of tc_skb_protocol(), which will
+use skb->protocol directly, but also parse and skip over any VLAN tags and
+return the inner protocol number instead.
+
+Also fix CE marking by implementing a version of INET_ECN_set_ce() that
+uses the same parsing routine.
+
+Fixes: ea82511518f4 ("sch_cake: Add NAT awareness to packet classifier")
+Fixes: b2100cc56fca ("sch_cake: Use tc_skb_protocol() helper for getting packet protocol")
+Fixes: 046f6fd5daef ("sched: Add Common Applications Kept Enhanced (cake) qdisc")
+Signed-off-by: Ilya Ponetayev <i.ponetaev@ndmsystems.com>
+[ squash original two patches, rewrite commit message ]
+Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
+Signed-off-by: Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>
+---
+ net/sched/sch_cake.c | 52 +++++++++++++++++++++++++++++++++++++++++---
+ 1 file changed, 49 insertions(+), 3 deletions(-)
+
+--- a/net/sched/sch_cake.c
++++ b/net/sched/sch_cake.c
+@@ -497,6 +497,52 @@ static bool cobalt_queue_empty(struct co
+ return down;
+ }
+
++static __be16 cake_skb_proto(const struct sk_buff *skb)
++{
++ unsigned int offset = skb_mac_offset(skb) + sizeof(struct ethhdr);
++ __be16 proto = skb->protocol;
++ struct vlan_hdr vhdr, *vh;
++
++ while (proto == htons(ETH_P_8021Q) || proto == htons(ETH_P_8021AD)) {
++ vh = skb_header_pointer(skb, offset, sizeof(vhdr), &vhdr);
++ if (!vh)
++ break;
++
++ proto = vh->h_vlan_encapsulated_proto;
++ offset += sizeof(vhdr);
++ }
++
++ return proto;
++}
++
++static int cake_set_ce(struct sk_buff *skb)
++{
++ int wlen = skb_network_offset(skb);
++
++ switch (cake_skb_proto(skb)) {
++ case htons(ETH_P_IP):
++ wlen += sizeof(struct iphdr);
++ if (!pskb_may_pull(skb, wlen) ||
++ skb_try_make_writable(skb, wlen))
++ return 0;
++
++ return IP_ECN_set_ce(ip_hdr(skb));
++
++ case htons(ETH_P_IPV6):
++ wlen += sizeof(struct ipv6hdr);
++ if (!pskb_may_pull(skb, wlen) ||
++ skb_try_make_writable(skb, wlen))
++ return 0;
++
++ return IP6_ECN_set_ce(skb, ipv6_hdr(skb));
++
++ default:
++ return 0;
++ }
++
++ return 0;
++}
++
+ /* Call this with a freshly dequeued packet for possible congestion marking.
+ * Returns true as an instruction to drop the packet, false for delivery.
+ */
+@@ -549,7 +595,7 @@ static bool cobalt_should_drop(struct co
+
+ if (next_due && vars->dropping) {
+ /* Use ECN mark if possible, otherwise drop */
+- drop = !(vars->ecn_marked = INET_ECN_set_ce(skb));
++ drop = !(vars->ecn_marked = cake_set_ce(skb));
+
+ vars->count++;
+ if (!vars->count)
+@@ -592,7 +638,7 @@ static bool cake_update_flowkeys(struct
+ bool rev = !skb->_nfct, upd = false;
+ __be32 ip;
+
+- if (tc_skb_protocol(skb) != htons(ETH_P_IP))
++ if (cake_skb_proto(skb) != htons(ETH_P_IP))
+ return false;
+
+ if (!nf_ct_get_tuple_skb(&tuple, skb))
+@@ -1557,7 +1603,7 @@ static u8 cake_handle_diffserv(struct sk
+ u16 *buf, buf_;
+ u8 dscp;
+
+- switch (tc_skb_protocol(skb)) {
++ switch (cake_skb_proto(skb)) {
+ case htons(ETH_P_IP):
+ buf = skb_header_pointer(skb, offset, sizeof(buf_), &buf_);
+ if (unlikely(!buf))
diff --git a/target/linux/generic/hack-5.4/641-sch_cake-fix-IP-protocol-handling-in-the-presence-of.patch b/target/linux/generic/hack-5.4/641-sch_cake-fix-IP-protocol-handling-in-the-presence-of.patch
new file mode 100644
index 0000000000..e651743c1d
--- /dev/null
+++ b/target/linux/generic/hack-5.4/641-sch_cake-fix-IP-protocol-handling-in-the-presence-of.patch
@@ -0,0 +1,114 @@
+From a00590d570212c3c633bd463cef8ec7377cc7993 Mon Sep 17 00:00:00 2001
+From: Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>
+Date: Tue, 30 Jun 2020 12:07:44 +0100
+Subject: [PATCH] sch_cake: fix IP protocol handling in the presence of VLAN
+ tags
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+From: Ilya Ponetayev <i.ponetaev@ndmsystems.com>
+
+CAKE was using the return value of tc_skb_protocol() and expecting it to be
+the IP protocol type. This can fail in the presence of QinQ VLAN tags,
+making CAKE unable to handle ECN marking and diffserv parsing in this case.
+Fix this by implementing our own version of tc_skb_protocol(), which will
+use skb->protocol directly, but also parse and skip over any VLAN tags and
+return the inner protocol number instead.
+
+Also fix CE marking by implementing a version of INET_ECN_set_ce() that
+uses the same parsing routine.
+
+Fixes: ea82511518f4 ("sch_cake: Add NAT awareness to packet classifier")
+Fixes: b2100cc56fca ("sch_cake: Use tc_skb_protocol() helper for getting packet protocol")
+Fixes: 046f6fd5daef ("sched: Add Common Applications Kept Enhanced (cake) qdisc")
+Signed-off-by: Ilya Ponetayev <i.ponetaev@ndmsystems.com>
+[ squash original two patches, rewrite commit message ]
+Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
+Signed-off-by: Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>
+---
+ net/sched/sch_cake.c | 52 +++++++++++++++++++++++++++++++++++++++++---
+ 1 file changed, 49 insertions(+), 3 deletions(-)
+
+--- a/net/sched/sch_cake.c
++++ b/net/sched/sch_cake.c
+@@ -497,6 +497,52 @@ static bool cobalt_queue_empty(struct co
+ return down;
+ }
+
++static __be16 cake_skb_proto(const struct sk_buff *skb)
++{
++ unsigned int offset = skb_mac_offset(skb) + sizeof(struct ethhdr);
++ __be16 proto = skb->protocol;
++ struct vlan_hdr vhdr, *vh;
++
++ while (proto == htons(ETH_P_8021Q) || proto == htons(ETH_P_8021AD)) {
++ vh = skb_header_pointer(skb, offset, sizeof(vhdr), &vhdr);
++ if (!vh)
++ break;
++
++ proto = vh->h_vlan_encapsulated_proto;
++ offset += sizeof(vhdr);
++ }
++
++ return proto;
++}
++
++static int cake_set_ce(struct sk_buff *skb)
++{
++ int wlen = skb_network_offset(skb);
++
++ switch (cake_skb_proto(skb)) {
++ case htons(ETH_P_IP):
++ wlen += sizeof(struct iphdr);
++ if (!pskb_may_pull(skb, wlen) ||
++ skb_try_make_writable(skb, wlen))
++ return 0;
++
++ return IP_ECN_set_ce(ip_hdr(skb));
++
++ case htons(ETH_P_IPV6):
++ wlen += sizeof(struct ipv6hdr);
++ if (!pskb_may_pull(skb, wlen) ||
++ skb_try_make_writable(skb, wlen))
++ return 0;
++
++ return IP6_ECN_set_ce(skb, ipv6_hdr(skb));
++
++ default:
++ return 0;
++ }
++
++ return 0;
++}
++
+ /* Call this with a freshly dequeued packet for possible congestion marking.
+ * Returns true as an instruction to drop the packet, false for delivery.
+ */
+@@ -549,7 +595,7 @@ static bool cobalt_should_drop(struct co
+
+ if (next_due && vars->dropping) {
+ /* Use ECN mark if possible, otherwise drop */
+- drop = !(vars->ecn_marked = INET_ECN_set_ce(skb));
++ drop = !(vars->ecn_marked = cake_set_ce(skb));
+
+ vars->count++;
+ if (!vars->count)
+@@ -592,7 +638,7 @@ static bool cake_update_flowkeys(struct
+ bool rev = !skb->_nfct, upd = false;
+ __be32 ip;
+
+- if (tc_skb_protocol(skb) != htons(ETH_P_IP))
++ if (cake_skb_proto(skb) != htons(ETH_P_IP))
+ return false;
+
+ if (!nf_ct_get_tuple_skb(&tuple, skb))
+@@ -1557,7 +1603,7 @@ static u8 cake_handle_diffserv(struct sk
+ u16 *buf, buf_;
+ u8 dscp;
+
+- switch (tc_skb_protocol(skb)) {
++ switch (cake_skb_proto(skb)) {
+ case htons(ETH_P_IP):
+ buf = skb_header_pointer(skb, offset, sizeof(buf_), &buf_);
+ if (unlikely(!buf))