| Message ID | 20170210233857.GA13996@linux-mips.org |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
From: Ralf Baechle <ralf@linux-mips.org> Date: Sat, 11 Feb 2017 00:38:57 +0100 > When sending ARP requests over AX.25 links the hwaddress in the neighbour > cache are not getting initialized. For such an incomplete arp entry > ax2asc2 will generate an empty string resulting in /proc/net/arp output > like the following: > > $ cat /proc/net/arp > IP address HW type Flags HW address Mask Device > 192.168.122.1 0x1 0x2 52:54:00:00:5d:5f * ens3 > 172.20.1.99 0x3 0x0 * bpq0 > > The missing field will confuse the procfs parsing of arp(8) resulting in > incorrect output for the device such as the following: > > $ arp > Address HWtype HWaddress Flags Mask Iface > gateway ether 52:54:00:00:5d:5f C ens3 > 172.20.1.99 (incomplete) ens3 > > This changes the content of /proc/net/arp to: > > $ cat /proc/net/arp > IP address HW type Flags HW address Mask Device > 172.20.1.99 0x3 0x0 * * bpq0 > 192.168.122.1 0x1 0x2 52:54:00:00:5d:5f * ens3 > > To do so it change ax2asc to put the string "*" in buf for a NULL address > argument. Finally the HW address field is left aligned in a 17 character > field (the length of an ethernet HW address in the usual hex notation) for > readability. > > Signed-off-by: Ralf Baechle <ralf@linux-mips.org> Applied, thanks Ralf.
diff --git a/net/ipv4/arp.c b/net/ipv4/arp.c index 89a8cac4..51b27ae 100644 --- a/net/ipv4/arp.c +++ b/net/ipv4/arp.c @@ -1263,7 +1263,7 @@ void __init arp_init(void) /* * ax25 -> ASCII conversion */ -static char *ax2asc2(ax25_address *a, char *buf) +static void ax2asc2(ax25_address *a, char *buf) { char c, *s; int n; @@ -1285,10 +1285,10 @@ static char *ax2asc2(ax25_address *a, char *buf) *s++ = n + '0'; *s++ = '\0'; - if (*buf == '\0' || *buf == '-') - return "*"; - - return buf; + if (*buf == '\0' || *buf == '-') { + buf[0] = '*'; + buf[1] = '\0'; + } } #endif /* CONFIG_AX25 */ @@ -1322,7 +1322,7 @@ static void arp_format_neigh_entry(struct seq_file *seq, } #endif sprintf(tbuf, "%pI4", n->primary_key); - seq_printf(seq, "%-16s 0x%-10x0x%-10x%s * %s\n", + seq_printf(seq, "%-16s 0x%-10x0x%-10x%-17s * %s\n", tbuf, hatype, arp_state_to_flags(n), hbuffer, dev->name); read_unlock(&n->lock); }
When sending ARP requests over AX.25 links the hwaddress in the neighbour cache are not getting initialized. For such an incomplete arp entry ax2asc2 will generate an empty string resulting in /proc/net/arp output like the following: $ cat /proc/net/arp IP address HW type Flags HW address Mask Device 192.168.122.1 0x1 0x2 52:54:00:00:5d:5f * ens3 172.20.1.99 0x3 0x0 * bpq0 The missing field will confuse the procfs parsing of arp(8) resulting in incorrect output for the device such as the following: $ arp Address HWtype HWaddress Flags Mask Iface gateway ether 52:54:00:00:5d:5f C ens3 172.20.1.99 (incomplete) ens3 This changes the content of /proc/net/arp to: $ cat /proc/net/arp IP address HW type Flags HW address Mask Device 172.20.1.99 0x3 0x0 * * bpq0 192.168.122.1 0x1 0x2 52:54:00:00:5d:5f * ens3 To do so it change ax2asc to put the string "*" in buf for a NULL address argument. Finally the HW address field is left aligned in a 17 character field (the length of an ethernet HW address in the usual hex notation) for readability. Signed-off-by: Ralf Baechle <ralf@linux-mips.org> --- net/ipv4/arp.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-)