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net: erspan: use bitfield instead of mask and offset
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Originally the erspan fields are defined as a group into a __be16 field,
and use mask and offset to access each field.  This is more costly due to
calling ntohs/htons.  The patch changes it to use bitfields.

Signed-off-by: William Tu <u9012063@gmail.com>
Acked-by: Pravin B Shelar <pshelar@ovn.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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William Tu authored and David S. Miller committed Jan 26, 2018
1 parent b89d06c commit c69de58
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Showing 3 changed files with 121 additions and 80 deletions.
127 changes: 94 additions & 33 deletions include/net/erspan.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -65,16 +65,30 @@
#define GRA_MASK 0x0006
#define O_MASK 0x0001

#define HWID_OFFSET 4
#define DIR_OFFSET 3

/* ERSPAN version 2 metadata header */
struct erspan_md2 {
__be32 timestamp;
__be16 sgt; /* security group tag */
__be16 flags;
#define P_OFFSET 15
#define FT_OFFSET 10
#define HWID_OFFSET 4
#define DIR_OFFSET 3
#define GRA_OFFSET 1
#if defined(__LITTLE_ENDIAN_BITFIELD)
__u8 hwid_upper:2,
ft:5,
p:1;
__u8 o:1,
gra:2,
dir:1,
hwid:4;
#elif defined(__BIG_ENDIAN_BITFIELD)
__u8 p:1,
ft:5,
hwid_upper:2;
__u8 hwid:4,
dir:1,
gra:2,
o:1;
#endif
};

enum erspan_encap_type {
Expand All @@ -95,15 +109,62 @@ struct erspan_metadata {
};

struct erspan_base_hdr {
__be16 ver_vlan;
#define VER_OFFSET 12
__be16 session_id;
#define COS_OFFSET 13
#define EN_OFFSET 11
#define BSO_OFFSET EN_OFFSET
#define T_OFFSET 10
#if defined(__LITTLE_ENDIAN_BITFIELD)
__u8 vlan_upper:4,
ver:4;
__u8 vlan:8;
__u8 session_id_upper:2,
t:1,
en:2,
cos:3;
__u8 session_id:8;
#elif defined(__BIG_ENDIAN_BITFIELD)
__u8 ver: 4,
vlan_upper:4;
__u8 vlan:8;
__u8 cos:3,
en:2,
t:1,
session_id_upper:2;
__u8 session_id:8;
#else
#error "Please fix <asm/byteorder.h>"
#endif
};

static inline void set_session_id(struct erspan_base_hdr *ershdr, u16 id)
{
ershdr->session_id = id & 0xff;
ershdr->session_id_upper = (id >> 8) & 0x3;
}

static inline u16 get_session_id(const struct erspan_base_hdr *ershdr)
{
return (ershdr->session_id_upper << 8) + ershdr->session_id;
}

static inline void set_vlan(struct erspan_base_hdr *ershdr, u16 vlan)
{
ershdr->vlan = vlan & 0xff;
ershdr->vlan_upper = (vlan >> 8) & 0xf;
}

static inline u16 get_vlan(const struct erspan_base_hdr *ershdr)
{
return (ershdr->vlan_upper << 8) + ershdr->vlan;
}

static inline void set_hwid(struct erspan_md2 *md2, u8 hwid)
{
md2->hwid = hwid & 0xf;
md2->hwid_upper = (hwid >> 4) & 0x3;
}

static inline u8 get_hwid(const struct erspan_md2 *md2)
{
return (md2->hwid_upper << 4) + md2->hwid;
}

static inline int erspan_hdr_len(int version)
{
return sizeof(struct erspan_base_hdr) +
Expand All @@ -120,7 +181,7 @@ static inline u8 tos_to_cos(u8 tos)
}

static inline void erspan_build_header(struct sk_buff *skb,
__be32 id, u32 index,
u32 id, u32 index,
bool truncate, bool is_ipv4)
{
struct ethhdr *eth = (struct ethhdr *)skb->data;
Expand Down Expand Up @@ -154,12 +215,12 @@ static inline void erspan_build_header(struct sk_buff *skb,
memset(ershdr, 0, sizeof(*ershdr) + ERSPAN_V1_MDSIZE);

/* Build base header */
ershdr->ver_vlan = htons((vlan_tci & VLAN_MASK) |
(ERSPAN_VERSION << VER_OFFSET));
ershdr->session_id = htons((u16)(ntohl(id) & ID_MASK) |
((tos_to_cos(tos) << COS_OFFSET) & COS_MASK) |
(enc_type << EN_OFFSET & EN_MASK) |
((truncate << T_OFFSET) & T_MASK));
ershdr->ver = ERSPAN_VERSION;
ershdr->cos = tos_to_cos(tos);
ershdr->en = enc_type;
ershdr->t = truncate;
set_vlan(ershdr, vlan_tci);
set_session_id(ershdr, id);

/* Build metadata */
ersmd = (struct erspan_metadata *)(ershdr + 1);
Expand Down Expand Up @@ -187,7 +248,7 @@ static inline __be32 erspan_get_timestamp(void)
}

static inline void erspan_build_header_v2(struct sk_buff *skb,
__be32 id, u8 direction, u16 hwid,
u32 id, u8 direction, u16 hwid,
bool truncate, bool is_ipv4)
{
struct ethhdr *eth = (struct ethhdr *)skb->data;
Expand All @@ -198,7 +259,6 @@ static inline void erspan_build_header_v2(struct sk_buff *skb,
__be16 tci;
} *qp;
u16 vlan_tci = 0;
u16 session_id;
u8 gra = 0; /* 100 usec */
u8 bso = 0; /* Bad/Short/Oversized */
u8 sgt = 0;
Expand All @@ -221,22 +281,23 @@ static inline void erspan_build_header_v2(struct sk_buff *skb,
memset(ershdr, 0, sizeof(*ershdr) + ERSPAN_V2_MDSIZE);

/* Build base header */
ershdr->ver_vlan = htons((vlan_tci & VLAN_MASK) |
(ERSPAN_VERSION2 << VER_OFFSET));
session_id = (u16)(ntohl(id) & ID_MASK) |
((tos_to_cos(tos) << COS_OFFSET) & COS_MASK) |
(bso << BSO_OFFSET & BSO_MASK) |
((truncate << T_OFFSET) & T_MASK);
ershdr->session_id = htons(session_id);
ershdr->ver = ERSPAN_VERSION2;
ershdr->cos = tos_to_cos(tos);
ershdr->en = bso;
ershdr->t = truncate;
set_vlan(ershdr, vlan_tci);
set_session_id(ershdr, id);

/* Build metadata */
md = (struct erspan_metadata *)(ershdr + 1);
md->u.md2.timestamp = erspan_get_timestamp();
md->u.md2.sgt = htons(sgt);
md->u.md2.flags = htons(((1 << P_OFFSET) & P_MASK) |
((hwid << HWID_OFFSET) & HWID_MASK) |
((direction << DIR_OFFSET) & DIR_MASK) |
((gra << GRA_OFFSET) & GRA_MASK));
md->u.md2.p = 1;
md->u.md2.ft = 0;
md->u.md2.dir = direction;
md->u.md2.gra = gra;
md->u.md2.o = 0;
set_hwid(&md->u.md2, hwid);
}

#endif
38 changes: 14 additions & 24 deletions net/ipv4/ip_gre.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -114,7 +114,7 @@ MODULE_PARM_DESC(log_ecn_error, "Log packets received with corrupted ECN");
static struct rtnl_link_ops ipgre_link_ops __read_mostly;
static int ipgre_tunnel_init(struct net_device *dev);
static void erspan_build_header(struct sk_buff *skb,
__be32 id, u32 index,
u32 id, u32 index,
bool truncate, bool is_ipv4);

static unsigned int ipgre_net_id __read_mostly;
Expand Down Expand Up @@ -273,12 +273,12 @@ static int erspan_rcv(struct sk_buff *skb, struct tnl_ptk_info *tpi,

iph = ip_hdr(skb);
ershdr = (struct erspan_base_hdr *)(skb->data + gre_hdr_len);
ver = (ntohs(ershdr->ver_vlan) & VER_MASK) >> VER_OFFSET;
ver = ershdr->ver;

/* The original GRE header does not have key field,
* Use ERSPAN 10-bit session ID as key.
*/
tpi->key = cpu_to_be32(ntohs(ershdr->session_id) & ID_MASK);
tpi->key = cpu_to_be32(get_session_id(ershdr));
tunnel = ip_tunnel_lookup(itn, skb->dev->ifindex,
tpi->flags | TUNNEL_KEY,
iph->saddr, iph->daddr, tpi->key);
Expand Down Expand Up @@ -324,14 +324,8 @@ static int erspan_rcv(struct sk_buff *skb, struct tnl_ptk_info *tpi,
if (ver == 1) {
tunnel->index = ntohl(pkt_md->u.index);
} else {
u16 md2_flags;
u16 dir, hwid;

md2_flags = ntohs(pkt_md->u.md2.flags);
dir = (md2_flags & DIR_MASK) >> DIR_OFFSET;
hwid = (md2_flags & HWID_MASK) >> HWID_OFFSET;
tunnel->dir = dir;
tunnel->hwid = hwid;
tunnel->dir = pkt_md->u.md2.dir;
tunnel->hwid = get_hwid(&pkt_md->u.md2);
}

}
Expand Down Expand Up @@ -615,19 +609,14 @@ static void erspan_fb_xmit(struct sk_buff *skb, struct net_device *dev,
}

if (version == 1) {
erspan_build_header(skb, tunnel_id_to_key32(key->tun_id),
erspan_build_header(skb, ntohl(tunnel_id_to_key32(key->tun_id)),
ntohl(md->u.index), truncate, true);
} else if (version == 2) {
u16 md2_flags;
u8 direction;
u16 hwid;

md2_flags = ntohs(md->u.md2.flags);
direction = (md2_flags & DIR_MASK) >> DIR_OFFSET;
hwid = (md2_flags & HWID_MASK) >> HWID_OFFSET;

erspan_build_header_v2(skb, tunnel_id_to_key32(key->tun_id),
direction, hwid, truncate, true);
erspan_build_header_v2(skb,
ntohl(tunnel_id_to_key32(key->tun_id)),
md->u.md2.dir,
get_hwid(&md->u.md2),
truncate, true);
} else {
goto err_free_rt;
}
Expand Down Expand Up @@ -733,10 +722,11 @@ static netdev_tx_t erspan_xmit(struct sk_buff *skb,

/* Push ERSPAN header */
if (tunnel->erspan_ver == 1)
erspan_build_header(skb, tunnel->parms.o_key, tunnel->index,
erspan_build_header(skb, ntohl(tunnel->parms.o_key),
tunnel->index,
truncate, true);
else
erspan_build_header_v2(skb, tunnel->parms.o_key,
erspan_build_header_v2(skb, ntohl(tunnel->parms.o_key),
tunnel->dir, tunnel->hwid,
truncate, true);

Expand Down
36 changes: 13 additions & 23 deletions net/ipv6/ip6_gre.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -513,8 +513,8 @@ static int ip6erspan_rcv(struct sk_buff *skb, int gre_hdr_len,

ipv6h = ipv6_hdr(skb);
ershdr = (struct erspan_base_hdr *)skb->data;
ver = (ntohs(ershdr->ver_vlan) & VER_MASK) >> VER_OFFSET;
tpi->key = cpu_to_be32(ntohs(ershdr->session_id) & ID_MASK);
ver = ershdr->ver;
tpi->key = cpu_to_be32(get_session_id(ershdr));

tunnel = ip6gre_tunnel_lookup(skb->dev,
&ipv6h->saddr, &ipv6h->daddr, tpi->key,
Expand Down Expand Up @@ -565,14 +565,8 @@ static int ip6erspan_rcv(struct sk_buff *skb, int gre_hdr_len,
if (ver == 1) {
tunnel->parms.index = ntohl(pkt_md->u.index);
} else {
u16 md2_flags;
u16 dir, hwid;

md2_flags = ntohs(pkt_md->u.md2.flags);
dir = (md2_flags & DIR_MASK) >> DIR_OFFSET;
hwid = (md2_flags & HWID_MASK) >> HWID_OFFSET;
tunnel->parms.dir = dir;
tunnel->parms.hwid = hwid;
tunnel->parms.dir = pkt_md->u.md2.dir;
tunnel->parms.hwid = get_hwid(&pkt_md->u.md2);
}

ip6_tnl_rcv(tunnel, skb, tpi, NULL, log_ecn_error);
Expand Down Expand Up @@ -925,6 +919,7 @@ static netdev_tx_t ip6erspan_tunnel_xmit(struct sk_buff *skb,
struct ip_tunnel_info *tun_info;
const struct ip_tunnel_key *key;
struct erspan_metadata *md;
__be32 tun_id;

tun_info = skb_tunnel_info(skb);
if (unlikely(!tun_info ||
Expand All @@ -944,23 +939,18 @@ static netdev_tx_t ip6erspan_tunnel_xmit(struct sk_buff *skb,
if (!md)
goto tx_err;

tun_id = tunnel_id_to_key32(key->tun_id);
if (md->version == 1) {
erspan_build_header(skb,
tunnel_id_to_key32(key->tun_id),
ntohl(tun_id),
ntohl(md->u.index), truncate,
false);
} else if (md->version == 2) {
u16 md2_flags;
u16 dir, hwid;

md2_flags = ntohs(md->u.md2.flags);
dir = (md2_flags & DIR_MASK) >> DIR_OFFSET;
hwid = (md2_flags & HWID_MASK) >> HWID_OFFSET;

erspan_build_header_v2(skb,
tunnel_id_to_key32(key->tun_id),
dir, hwid, truncate,
false);
ntohl(tun_id),
md->u.md2.dir,
get_hwid(&md->u.md2),
truncate, false);
}
} else {
switch (skb->protocol) {
Expand All @@ -982,11 +972,11 @@ static netdev_tx_t ip6erspan_tunnel_xmit(struct sk_buff *skb,
}

if (t->parms.erspan_ver == 1)
erspan_build_header(skb, t->parms.o_key,
erspan_build_header(skb, ntohl(t->parms.o_key),
t->parms.index,
truncate, false);
else
erspan_build_header_v2(skb, t->parms.o_key,
erspan_build_header_v2(skb, ntohl(t->parms.o_key),
t->parms.dir,
t->parms.hwid,
truncate, false);
Expand Down

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