2016-02-02 13:39:17

by Felix Fietkau

[permalink] [raw]
Subject: [PATCH 1/3] mac80211: move A-MSDU skb_linearize call to ieee80211_amsdu_to_8023s

Prepararation for zero-copy A-MSDU support with page fragment SKBs

Signed-off-by: Felix Fietkau <[email protected]>
---
net/mac80211/rx.c | 3 ---
net/wireless/util.c | 3 +++
2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 664e886..1e9308e 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -2203,9 +2203,6 @@ ieee80211_rx_h_amsdu(struct ieee80211_rx_data *rx)
skb->dev = dev;
__skb_queue_head_init(&frame_list);

- if (skb_linearize(skb))
- return RX_DROP_UNUSABLE;
-
ieee80211_amsdu_to_8023s(skb, &frame_list, dev->dev_addr,
rx->sdata->vif.type,
rx->local->hw.extra_tx_headroom, true);
diff --git a/net/wireless/util.c b/net/wireless/util.c
index 9277042..6a40769 100644
--- a/net/wireless/util.c
+++ b/net/wireless/util.c
@@ -657,6 +657,9 @@ void ieee80211_amsdu_to_8023s(struct sk_buff *skb, struct sk_buff_head *list,
int remaining, err;
u8 dst[ETH_ALEN], src[ETH_ALEN];

+ if (skb_linearize(skb))
+ goto out;
+
if (has_80211_header) {
err = ieee80211_data_to_8023(skb, addr, iftype);
if (err)
--
2.2.2



2016-02-02 13:39:17

by Felix Fietkau

[permalink] [raw]
Subject: [PATCH 2/3] cfg80211: add function for 802.3 conversion with separate output buffer

Use skb_copy_bits in preparation for allowing fragmented skbs

Signed-off-by: Felix Fietkau <[email protected]>
---
net/wireless/util.c | 106 ++++++++++++++++++++++++++--------------------------
1 file changed, 53 insertions(+), 53 deletions(-)

diff --git a/net/wireless/util.c b/net/wireless/util.c
index 6a40769..f75f601 100644
--- a/net/wireless/util.c
+++ b/net/wireless/util.c
@@ -393,9 +393,9 @@ unsigned int ieee80211_get_hdrlen_from_skb(const struct sk_buff *skb)
}
EXPORT_SYMBOL(ieee80211_get_hdrlen_from_skb);

-unsigned int ieee80211_get_mesh_hdrlen(struct ieee80211s_hdr *meshhdr)
+static unsigned int __ieee80211_get_mesh_hdrlen(u8 flags)
{
- int ae = meshhdr->flags & MESH_FLAGS_AE;
+ int ae = flags & MESH_FLAGS_AE;
/* 802.11-2012, 8.2.4.7.3 */
switch (ae) {
default:
@@ -407,21 +407,31 @@ unsigned int ieee80211_get_mesh_hdrlen(struct ieee80211s_hdr *meshhdr)
return 18;
}
}
+
+unsigned int ieee80211_get_mesh_hdrlen(struct ieee80211s_hdr *meshhdr)
+{
+ return __ieee80211_get_mesh_hdrlen(meshhdr->flags);
+}
EXPORT_SYMBOL(ieee80211_get_mesh_hdrlen);

-int ieee80211_data_to_8023(struct sk_buff *skb, const u8 *addr,
- enum nl80211_iftype iftype)
+static int __ieee80211_data_to_8023(struct sk_buff *skb, struct ethhdr *ehdr,
+ const u8 *addr, enum nl80211_iftype iftype)
{
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
- u16 hdrlen, ethertype;
- u8 *payload;
- u8 dst[ETH_ALEN];
- u8 src[ETH_ALEN] __aligned(2);
+ struct {
+ u8 hdr[ETH_ALEN] __aligned(2);
+ __be16 proto;
+ } payload;
+ struct ethhdr tmp;
+ u16 hdrlen;
+ u8 mesh_flags = 0;

if (unlikely(!ieee80211_is_data_present(hdr->frame_control)))
return -1;

hdrlen = ieee80211_hdrlen(hdr->frame_control);
+ if (skb->len < hdrlen + 8)
+ return -1;

/* convert IEEE 802.11 header + possible LLC headers into Ethernet
* header
@@ -432,8 +442,11 @@ int ieee80211_data_to_8023(struct sk_buff *skb, const u8 *addr,
* 1 0 BSSID SA DA n/a
* 1 1 RA TA DA SA
*/
- memcpy(dst, ieee80211_get_DA(hdr), ETH_ALEN);
- memcpy(src, ieee80211_get_SA(hdr), ETH_ALEN);
+ memcpy(tmp.h_dest, ieee80211_get_DA(hdr), ETH_ALEN);
+ memcpy(tmp.h_source, ieee80211_get_SA(hdr), ETH_ALEN);
+
+ if (iftype == NL80211_IFTYPE_MESH_POINT)
+ skb_copy_bits(skb, hdrlen, &mesh_flags, 1);

switch (hdr->frame_control &
cpu_to_le16(IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS)) {
@@ -450,44 +463,31 @@ int ieee80211_data_to_8023(struct sk_buff *skb, const u8 *addr,
iftype != NL80211_IFTYPE_STATION))
return -1;
if (iftype == NL80211_IFTYPE_MESH_POINT) {
- struct ieee80211s_hdr *meshdr =
- (struct ieee80211s_hdr *) (skb->data + hdrlen);
- /* make sure meshdr->flags is on the linear part */
- if (!pskb_may_pull(skb, hdrlen + 1))
- return -1;
- if (meshdr->flags & MESH_FLAGS_AE_A4)
+ if (mesh_flags & MESH_FLAGS_AE_A4)
return -1;
- if (meshdr->flags & MESH_FLAGS_AE_A5_A6) {
+ if (mesh_flags & MESH_FLAGS_AE_A5_A6) {
skb_copy_bits(skb, hdrlen +
offsetof(struct ieee80211s_hdr, eaddr1),
- dst, ETH_ALEN);
- skb_copy_bits(skb, hdrlen +
- offsetof(struct ieee80211s_hdr, eaddr2),
- src, ETH_ALEN);
+ tmp.h_dest, 2 * ETH_ALEN);
}
- hdrlen += ieee80211_get_mesh_hdrlen(meshdr);
+ hdrlen += __ieee80211_get_mesh_hdrlen(mesh_flags);
}
break;
case cpu_to_le16(IEEE80211_FCTL_FROMDS):
if ((iftype != NL80211_IFTYPE_STATION &&
iftype != NL80211_IFTYPE_P2P_CLIENT &&
iftype != NL80211_IFTYPE_MESH_POINT) ||
- (is_multicast_ether_addr(dst) &&
- ether_addr_equal(src, addr)))
+ (is_multicast_ether_addr(tmp.h_dest) &&
+ ether_addr_equal(tmp.h_source, addr)))
return -1;
if (iftype == NL80211_IFTYPE_MESH_POINT) {
- struct ieee80211s_hdr *meshdr =
- (struct ieee80211s_hdr *) (skb->data + hdrlen);
- /* make sure meshdr->flags is on the linear part */
- if (!pskb_may_pull(skb, hdrlen + 1))
+ if (mesh_flags & MESH_FLAGS_AE_A5_A6)
return -1;
- if (meshdr->flags & MESH_FLAGS_AE_A5_A6)
- return -1;
- if (meshdr->flags & MESH_FLAGS_AE_A4)
+ if (mesh_flags & MESH_FLAGS_AE_A4)
skb_copy_bits(skb, hdrlen +
offsetof(struct ieee80211s_hdr, eaddr1),
- src, ETH_ALEN);
- hdrlen += ieee80211_get_mesh_hdrlen(meshdr);
+ tmp.h_source, ETH_ALEN);
+ hdrlen += __ieee80211_get_mesh_hdrlen(mesh_flags);
}
break;
case cpu_to_le16(0):
@@ -498,33 +498,33 @@ int ieee80211_data_to_8023(struct sk_buff *skb, const u8 *addr,
break;
}

- if (!pskb_may_pull(skb, hdrlen + 8))
- return -1;
-
- payload = skb->data + hdrlen;
- ethertype = (payload[6] << 8) | payload[7];
+ skb_copy_bits(skb, hdrlen, &payload, sizeof(payload));
+ tmp.h_proto = payload.proto;

- if (likely((ether_addr_equal(payload, rfc1042_header) &&
- ethertype != ETH_P_AARP && ethertype != ETH_P_IPX) ||
- ether_addr_equal(payload, bridge_tunnel_header))) {
+ if (likely((ether_addr_equal(payload.hdr, rfc1042_header) &&
+ tmp.h_proto != htons(ETH_P_AARP) &&
+ tmp.h_proto != htons(ETH_P_IPX)) ||
+ ether_addr_equal(payload.hdr, bridge_tunnel_header)))
/* remove RFC1042 or Bridge-Tunnel encapsulation and
* replace EtherType */
- skb_pull(skb, hdrlen + 6);
- memcpy(skb_push(skb, ETH_ALEN), src, ETH_ALEN);
- memcpy(skb_push(skb, ETH_ALEN), dst, ETH_ALEN);
- } else {
- struct ethhdr *ehdr;
- __be16 len;
+ hdrlen += ETH_ALEN + 2;
+ else
+ tmp.h_proto = htons(skb->len);
+
+ pskb_pull(skb, hdrlen);

- skb_pull(skb, hdrlen);
- len = htons(skb->len);
+ if (!ehdr)
ehdr = (struct ethhdr *) skb_push(skb, sizeof(struct ethhdr));
- memcpy(ehdr->h_dest, dst, ETH_ALEN);
- memcpy(ehdr->h_source, src, ETH_ALEN);
- ehdr->h_proto = len;
- }
+ memcpy(ehdr, &tmp, sizeof(tmp));
+
return 0;
}
+
+int ieee80211_data_to_8023(struct sk_buff *skb, const u8 *addr,
+ enum nl80211_iftype iftype)
+{
+ return __ieee80211_data_to_8023(skb, NULL, addr, iftype);
+}
EXPORT_SYMBOL(ieee80211_data_to_8023);

int ieee80211_data_from_8023(struct sk_buff *skb, const u8 *addr,
--
2.2.2


2016-02-02 13:39:17

by Felix Fietkau

[permalink] [raw]
Subject: [PATCH 3/3] cfg80211: add support for non-linear skbs in ieee80211_amsdu_to_8023s

Signed-off-by: Felix Fietkau <[email protected]>
---
net/wireless/util.c | 100 +++++++++++++++++++++++++---------------------------
1 file changed, 49 insertions(+), 51 deletions(-)

diff --git a/net/wireless/util.c b/net/wireless/util.c
index f75f601..e0cf5ae 100644
--- a/net/wireless/util.c
+++ b/net/wireless/util.c
@@ -644,73 +644,75 @@ int ieee80211_data_from_8023(struct sk_buff *skb, const u8 *addr,
}
EXPORT_SYMBOL(ieee80211_data_from_8023);

+static struct sk_buff *
+__ieee80211_amsdu_copy(struct sk_buff *skb, unsigned int hlen,
+ int offset, int len)
+{
+ struct sk_buff *frame;
+
+ if (skb->len - offset < len)
+ return NULL;
+
+ /*
+ * Allocate and reserve two bytes more for payload
+ * alignment since sizeof(struct ethhdr) is 14.
+ */
+ frame = dev_alloc_skb(hlen + sizeof(struct ethhdr) + 2 + len);
+
+ skb_reserve(frame, hlen + sizeof(struct ethhdr) + 2);
+ skb_copy_bits(skb, offset, skb_put(frame, len), len);
+
+ return frame;
+}

void ieee80211_amsdu_to_8023s(struct sk_buff *skb, struct sk_buff_head *list,
const u8 *addr, enum nl80211_iftype iftype,
const unsigned int extra_headroom,
bool has_80211_header)
{
+ unsigned int hlen = ALIGN(extra_headroom, 4);
struct sk_buff *frame = NULL;
u16 ethertype;
u8 *payload;
- const struct ethhdr *eth;
- int remaining, err;
- u8 dst[ETH_ALEN], src[ETH_ALEN];
-
- if (skb_linearize(skb))
- goto out;
+ int offset = 0, remaining, err;
+ struct ethhdr eth;
+ bool reuse_skb = true;
+ bool last = false;

if (has_80211_header) {
- err = ieee80211_data_to_8023(skb, addr, iftype);
+ err = __ieee80211_data_to_8023(skb, &eth, addr, iftype);
if (err)
goto out;
-
- /* skip the wrapping header */
- eth = (struct ethhdr *) skb_pull(skb, sizeof(struct ethhdr));
- if (!eth)
- goto out;
- } else {
- eth = (struct ethhdr *) skb->data;
}

- while (skb != frame) {
+ while (!last) {
+ unsigned int subframe_len;
+ int len;
u8 padding;
- __be16 len = eth->h_proto;
- unsigned int subframe_len = sizeof(struct ethhdr) + ntohs(len);
-
- remaining = skb->len;
- memcpy(dst, eth->h_dest, ETH_ALEN);
- memcpy(src, eth->h_source, ETH_ALEN);

+ skb_copy_bits(skb, offset, &eth, sizeof(eth));
+ len = ntohs(eth.h_proto);
+ subframe_len = sizeof(struct ethhdr) + len;
padding = (4 - subframe_len) & 0x3;
+
/* the last MSDU has no padding */
+ remaining = skb->len - offset;
if (subframe_len > remaining)
goto purge;

- skb_pull(skb, sizeof(struct ethhdr));
+ offset += sizeof(struct ethhdr);
/* reuse skb for the last subframe */
- if (remaining <= subframe_len + padding)
+ last = remaining <= subframe_len + padding;
+ if (!skb_is_nonlinear(skb) && last) {
+ skb_pull(skb, offset);
frame = skb;
- else {
- unsigned int hlen = ALIGN(extra_headroom, 4);
- /*
- * Allocate and reserve two bytes more for payload
- * alignment since sizeof(struct ethhdr) is 14.
- */
- frame = dev_alloc_skb(hlen + subframe_len + 2);
+ reuse_skb = true;
+ } else {
+ frame = __ieee80211_amsdu_copy(skb, hlen, offset, len);
if (!frame)
goto purge;

- skb_reserve(frame, hlen + sizeof(struct ethhdr) + 2);
- memcpy(skb_put(frame, ntohs(len)), skb->data,
- ntohs(len));
-
- eth = (struct ethhdr *)skb_pull(skb, ntohs(len) +
- padding);
- if (!eth) {
- dev_kfree_skb(frame);
- goto purge;
- }
+ offset += len + padding;
}

skb_reset_network_header(frame);
@@ -719,24 +721,20 @@ void ieee80211_amsdu_to_8023s(struct sk_buff *skb, struct sk_buff_head *list,

payload = frame->data;
ethertype = (payload[6] << 8) | payload[7];
-
if (likely((ether_addr_equal(payload, rfc1042_header) &&
ethertype != ETH_P_AARP && ethertype != ETH_P_IPX) ||
ether_addr_equal(payload, bridge_tunnel_header))) {
- /* remove RFC1042 or Bridge-Tunnel
- * encapsulation and replace EtherType */
- skb_pull(frame, 6);
- memcpy(skb_push(frame, ETH_ALEN), src, ETH_ALEN);
- memcpy(skb_push(frame, ETH_ALEN), dst, ETH_ALEN);
- } else {
- memcpy(skb_push(frame, sizeof(__be16)), &len,
- sizeof(__be16));
- memcpy(skb_push(frame, ETH_ALEN), src, ETH_ALEN);
- memcpy(skb_push(frame, ETH_ALEN), dst, ETH_ALEN);
+ eth.h_proto = htons(ethertype);
+ skb_pull(frame, ETH_ALEN + 2);
}
+
+ memcpy(skb_push(frame, sizeof(eth)), &eth, sizeof(eth));
__skb_queue_tail(list, frame);
}

+ if (!reuse_skb)
+ dev_kfree_skb(skb);
+
return;

purge:
--
2.2.2


2016-02-02 15:18:17

by Johannes Berg

[permalink] [raw]
Subject: Re: [PATCH 1/3] mac80211: move A-MSDU skb_linearize call to ieee80211_amsdu_to_8023s

all three applied, I fixed some whitespace damage (bad indent) on the
last patch

johannes