net: ipv4: Convert IP network timestamps to be y2038 safe

ICMP timestamp messages and IP source route options require
timestamps to be in milliseconds modulo 24 hours from
midnight UT format.

Add inet_current_timestamp() function to support this. The function
returns the required timestamp in network byte order.

Timestamp calculation is also changed to call ktime_get_real_ts64()
which uses struct timespec64. struct timespec64 is y2038 safe.
Previously it called getnstimeofday() which uses struct timespec.
struct timespec is not y2038 safe.

Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
Cc: James Morris <jmorris@namei.org>
Cc: Patrick McHardy <kaber@trash.net>
Acked-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/ip.h b/include/net/ip.h
index cbb134b2f0e4ff2ae81aa6e45a351a2246605786..fad74d323bd6b324ef24ff7ff0ce03140c58e1dd 100644 (file)
--- a/include/net/ip.h
+++ b/include/net/ip.h
@@ -240,6 +240,8 @@ static inline int inet_is_local_reserved_port(struct net *net, int port)
 }
 #endif
 
+__be32 inet_current_timestamp(void);
+
 /* From inetpeer.c */
 extern int inet_peer_threshold;
 extern int inet_peer_minttl;

diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index 209d1ed2895444bfd90d2eb12f6942d984be40d5..0cc923f83e107b429521ef809a5a308c06680e7e 100644 (file)
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -1380,6 +1380,32 @@ static struct sk_buff **inet_gro_receive(struct sk_buff **head,
        return pp;
 }
 
+#define SECONDS_PER_DAY        86400
+
+/* inet_current_timestamp - Return IP network timestamp
+ *
+ * Return milliseconds since midnight in network byte order.
+ */
+__be32 inet_current_timestamp(void)
+{
+       u32 secs;
+       u32 msecs;
+       struct timespec64 ts;
+
+       ktime_get_real_ts64(&ts);
+
+       /* Get secs since midnight. */
+       (void)div_u64_rem(ts.tv_sec, SECONDS_PER_DAY, &secs);
+       /* Convert to msecs. */
+       msecs = secs * MSEC_PER_SEC;
+       /* Convert nsec to msec. */
+       msecs += (u32)ts.tv_nsec / NSEC_PER_MSEC;
+
+       /* Convert to network byte order. */
+       return htons(msecs);
+}
+EXPORT_SYMBOL(inet_current_timestamp);
+
 int inet_recv_error(struct sock *sk, struct msghdr *msg, int len, int *addr_len)
 {
        if (sk->sk_family == AF_INET)

diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c
index 36e26977c9088c1dbd09cd13e9a5e2c43369fe31..6333489771ed07bb2509500a2e48fed05643281a 100644 (file)
--- a/net/ipv4/icmp.c
+++ b/net/ipv4/icmp.c
@@ -931,7 +931,6 @@ static bool icmp_echo(struct sk_buff *skb)
  */
 static bool icmp_timestamp(struct sk_buff *skb)
 {
-       struct timespec tv;
        struct icmp_bxm icmp_param;
        /*
         *      Too short.
@@ -942,9 +941,7 @@ static bool icmp_timestamp(struct sk_buff *skb)
        /*
         *      Fill in the current time as ms since midnight UT:
         */
-       getnstimeofday(&tv);
-       icmp_param.data.times[1] = htonl((tv.tv_sec % 86400) * MSEC_PER_SEC +
-                                        tv.tv_nsec / NSEC_PER_MSEC);
+       icmp_param.data.times[1] = inet_current_timestamp();
        icmp_param.data.times[2] = icmp_param.data.times[1];
        if (skb_copy_bits(skb, 0, &icmp_param.data.times[0], 4))
                BUG();

diff --git a/net/ipv4/ip_options.c b/net/ipv4/ip_options.c
index bd246792360b4b8dcda2c13328ea5f01bb603e06..4d158ff1def1a8fae218b268c7e66224eed95adf 100644 (file)
--- a/net/ipv4/ip_options.c
+++ b/net/ipv4/ip_options.c
@@ -58,10 +58,9 @@ void ip_options_build(struct sk_buff *skb, struct ip_options *opt,
                if (opt->ts_needaddr)
                        ip_rt_get_source(iph+opt->ts+iph[opt->ts+2]-9, skb, rt);
                if (opt->ts_needtime) {
-                       struct timespec tv;
                        __be32 midtime;
-                       getnstimeofday(&tv);
-                       midtime = htonl((tv.tv_sec % 86400) * MSEC_PER_SEC + tv.tv_nsec / NSEC_PER_MSEC);
+
+                       midtime = inet_current_timestamp();
                        memcpy(iph+opt->ts+iph[opt->ts+2]-5, &midtime, 4);
                }
                return;
@@ -415,11 +414,10 @@ int ip_options_compile(struct net *net,
                                        break;
                                }
                                if (timeptr) {
-                                       struct timespec tv;
-                                       u32  midtime;
-                                       getnstimeofday(&tv);
-                                       midtime = (tv.tv_sec % 86400) * MSEC_PER_SEC + tv.tv_nsec / NSEC_PER_MSEC;
-                                       put_unaligned_be32(midtime, timeptr);
+                                       __be32 midtime;
+
+                                       midtime = inet_current_timestamp();
+                                       memcpy(timeptr, &midtime, 4);
                                        opt->is_changed = 1;
                                }
                        } else if ((optptr[3]&0xF) != IPOPT_TS_PRESPEC) {