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Subject[PATCH] [v3] infiniband: i40iw, nes: don't use wall time for TCP sequence numbers
Date
The nes infiniband driver uses current_kernel_time() to get a nanosecond
granunarity timestamp to initialize its tcp sequence counters. This is
one of only a few remaining users of that deprecated function, so we
should try to get rid of it.

Aside from using a deprecated API, there are several problems I see here:

- Using a CLOCK_REALTIME based time source makes it predictable in
case the time base is synchronized.
- Using a coarse timestamp means it only gets updated once per jiffie,
making it even more predictable in order to avoid having to access
the hardware clock source
- The upper 2 bits are always zero because the nanoseconds are at most
999999999.

For the Linux TCP implementation, we use secure_tcp_seq(), which appears
to be appropriate here as well, and solves all the above problems.

i40iw uses a variant of the same code, so I do that same thing there
for ipv4. Unlike nes, i40e also supports ipv6, which needs to call
secure_tcpv6_seq instead.

Acked-by: Shiraz Saleem <shiraz.saleem@intel.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
v2: use secure_tcpv6_seq for IPv6 support as suggested by Shiraz Saleem.
v3: add a soft IPv6 dependency to prevent a link error with CONFIG_IPV6=m,
this now forces i40iw to be a module as well, add an IS_ENABLED()
check to avoid calling it when IPV6 is completely disabled.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
drivers/infiniband/hw/i40iw/Kconfig | 1 +
drivers/infiniband/hw/i40iw/i40iw_cm.c | 26 +++++++++++++++++++++-----
drivers/infiniband/hw/nes/nes_cm.c | 8 +++++---
net/core/secure_seq.c | 1 +
4 files changed, 28 insertions(+), 8 deletions(-)

diff --git a/drivers/infiniband/hw/i40iw/Kconfig b/drivers/infiniband/hw/i40iw/Kconfig
index 2962979c06e9..d867ef1ac72a 100644
--- a/drivers/infiniband/hw/i40iw/Kconfig
+++ b/drivers/infiniband/hw/i40iw/Kconfig
@@ -1,6 +1,7 @@
config INFINIBAND_I40IW
tristate "Intel(R) Ethernet X722 iWARP Driver"
depends on INET && I40E
+ depends on IPV6 || !IPV6
depends on PCI
select GENERIC_ALLOCATOR
---help---
diff --git a/drivers/infiniband/hw/i40iw/i40iw_cm.c b/drivers/infiniband/hw/i40iw/i40iw_cm.c
index 7b2655128b9f..423818a7d333 100644
--- a/drivers/infiniband/hw/i40iw/i40iw_cm.c
+++ b/drivers/infiniband/hw/i40iw/i40iw_cm.c
@@ -57,6 +57,7 @@
#include <net/addrconf.h>
#include <net/ip6_route.h>
#include <net/ip_fib.h>
+#include <net/secure_seq.h>
#include <net/tcp.h>
#include <asm/checksum.h>

@@ -2164,7 +2165,6 @@ static struct i40iw_cm_node *i40iw_make_cm_node(
struct i40iw_cm_listener *listener)
{
struct i40iw_cm_node *cm_node;
- struct timespec ts;
int oldarpindex;
int arpindex;
struct net_device *netdev = iwdev->netdev;
@@ -2214,10 +2214,26 @@ static struct i40iw_cm_node *i40iw_make_cm_node(
cm_node->tcp_cntxt.rcv_wscale = I40IW_CM_DEFAULT_RCV_WND_SCALE;
cm_node->tcp_cntxt.rcv_wnd =
I40IW_CM_DEFAULT_RCV_WND_SCALED >> I40IW_CM_DEFAULT_RCV_WND_SCALE;
- ts = current_kernel_time();
- cm_node->tcp_cntxt.loc_seq_num = ts.tv_nsec;
- cm_node->tcp_cntxt.mss = (cm_node->ipv4) ? (iwdev->vsi.mtu - I40IW_MTU_TO_MSS_IPV4) :
- (iwdev->vsi.mtu - I40IW_MTU_TO_MSS_IPV6);
+ if (cm_node->ipv4) {
+ cm_node->tcp_cntxt.loc_seq_num = secure_tcp_seq(htonl(cm_node->loc_addr[0]),
+ htonl(cm_node->rem_addr[0]),
+ htons(cm_node->loc_port),
+ htons(cm_node->rem_port));
+ cm_node->tcp_cntxt.mss = iwdev->vsi.mtu - I40IW_MTU_TO_MSS_IPV4;
+ } else if (IS_ENABLED(CONFIG_IPV6)) {
+ __be32 loc[4] = {
+ htonl(cm_node->loc_addr[0]), htonl(cm_node->loc_addr[1]),
+ htonl(cm_node->loc_addr[2]), htonl(cm_node->loc_addr[3])
+ };
+ __be32 rem[4] = {
+ htonl(cm_node->rem_addr[0]), htonl(cm_node->rem_addr[1]),
+ htonl(cm_node->rem_addr[2]), htonl(cm_node->rem_addr[3])
+ };
+ cm_node->tcp_cntxt.loc_seq_num = secure_tcpv6_seq(loc, rem,
+ htons(cm_node->loc_port),
+ htons(cm_node->rem_port));
+ cm_node->tcp_cntxt.mss = iwdev->vsi.mtu - I40IW_MTU_TO_MSS_IPV6;
+ }

cm_node->iwdev = iwdev;
cm_node->dev = &iwdev->sc_dev;
diff --git a/drivers/infiniband/hw/nes/nes_cm.c b/drivers/infiniband/hw/nes/nes_cm.c
index 6cdfbf8c5674..2b67ace5b614 100644
--- a/drivers/infiniband/hw/nes/nes_cm.c
+++ b/drivers/infiniband/hw/nes/nes_cm.c
@@ -58,6 +58,7 @@
#include <net/neighbour.h>
#include <net/route.h>
#include <net/ip_fib.h>
+#include <net/secure_seq.h>
#include <net/tcp.h>
#include <linux/fcntl.h>

@@ -1445,7 +1446,6 @@ static struct nes_cm_node *make_cm_node(struct nes_cm_core *cm_core,
struct nes_cm_listener *listener)
{
struct nes_cm_node *cm_node;
- struct timespec ts;
int oldarpindex = 0;
int arpindex = 0;
struct nes_device *nesdev;
@@ -1496,8 +1496,10 @@ static struct nes_cm_node *make_cm_node(struct nes_cm_core *cm_core,
cm_node->tcp_cntxt.rcv_wscale = NES_CM_DEFAULT_RCV_WND_SCALE;
cm_node->tcp_cntxt.rcv_wnd = NES_CM_DEFAULT_RCV_WND_SCALED >>
NES_CM_DEFAULT_RCV_WND_SCALE;
- ts = current_kernel_time();
- cm_node->tcp_cntxt.loc_seq_num = htonl(ts.tv_nsec);
+ cm_node->tcp_cntxt.loc_seq_num = secure_tcp_seq(htonl(cm_node->loc_addr),
+ htonl(cm_node->rem_addr),
+ htons(cm_node->loc_port),
+ htons(cm_node->rem_port));
cm_node->tcp_cntxt.mss = nesvnic->max_frame_size - sizeof(struct iphdr) -
sizeof(struct tcphdr) - ETH_HLEN - VLAN_HLEN;
cm_node->tcp_cntxt.rcv_nxt = 0;
diff --git a/net/core/secure_seq.c b/net/core/secure_seq.c
index 7232274de334..af6ad467ed61 100644
--- a/net/core/secure_seq.c
+++ b/net/core/secure_seq.c
@@ -140,6 +140,7 @@ u32 secure_tcp_seq(__be32 saddr, __be32 daddr,
&net_secret);
return seq_scale(hash);
}
+EXPORT_SYMBOL_GPL(secure_tcp_seq);

u32 secure_ipv4_port_ephemeral(__be32 saddr, __be32 daddr, __be16 dport)
{
--
2.9.0
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