[PATCH v2 1/2] rtnl_link: decode ifinfomsg netlink attributes
JingPiao Chen
chenjingpiao at gmail.com
Sun Aug 20 08:06:25 UTC 2017
On Sun, Aug 20, 2017 at 01:33:53AM +0300, Dmitry V. Levin wrote:
> On Sat, Aug 19, 2017 at 09:50:10AM +0800, JingPiao Chen wrote:
> > * configure.ac (AC_CHECK_HEADERS): Add linux/if_link.h.
> > (AC_CHECK_TYPES): Check for struct rtnl_link_stats64 in linux/if_link.h.
> > (AC_CHECK_MEMBERS): Check for rx_nohandler field
> > in struct rtnl_link_stats and struct rtnl_link_stats64.
> > * rtnl_link.c: Include <arpa/inet.h>, <linux/if_arp.h>,
> > <linux/if_link.h> and <linux/netdevice.h>.
> > (min_ifla_address_len, ifla_address_default_decoder,
> > ifla_address_type_specific_decoder,
> > decode_ifla_address, decode_rtnl_link_stats,
> > decode_rtnl_link_ifmap, decode_rtnl_link_stats64,
> > print_item_id, decode_ifla_phys_item_id): New functions.
> > (decode_ifla_phys_item_id): New array.
>
> How could decode_ifla_phys_item_id be both a function and an array?
>
> > (decode_ifinfomsg): Use it.
> > ---
[...]
> > +static bool
> > +decode_rtnl_link_stats(struct tcb *const tcp,
> > + const kernel_ulong_t addr,
> > + const unsigned int len,
> > + const void *const opaque_data)
> > +{
> > + struct rtnl_link_stats st;
> > +
> > + if (len < sizeof(st))
> > + return false;
>
> The kernel may not transfer struct rtnl_link_stats.rx_nohandler despite
> the latter being defined by linux/if_link.h, e.g. if the kernel uses
> an older version of struct rtnl_link_stats.
> The minimal size is therefore not sizeof(struct rtnl_link_stats)
> but offsetofend(struct rtnl_link_stats, tx_compressed).
>
> Likewise, with struct rtnl_link_stats64.rx_nohandler.
You means:
struct rtnl_link_stats st;
const unsigned int sizeof_stat =
offsetofend(struct rtnl_link_stats, tx_compressed);
if (len < sizeof_stat)
return false;
else if (!umoven_or_printaddr(tcp, addr, sizeof_stat, &st)) {
...
I can not understand where I can know kernel not transfer
struct rtnl_link_stats.rx_nohandler.
net/core/rtnetlink.c:
static noinline_for_stack int rtnl_fill_stats(struct sk_buff *skb,
struct net_device *dev)
{
struct rtnl_link_stats64 *sp;
struct nlattr *attr;
/* It seem here include rtnl_link_stats64.rx_nohandler */
attr = nla_reserve_64bit(skb, IFLA_STATS64,
sizeof(struct rtnl_link_stats64), IFLA_PAD);
if (!attr)
return -EMSGSIZE;
sp = nla_data(attr);
dev_get_stats(dev, sp);
/* It seem here include rtnl_link_stats.rx_nohandler */
attr = nla_reserve(skb, IFLA_STATS,
sizeof(struct rtnl_link_stats));
if (!attr)
return -EMSGSIZE;
copy_rtnl_link_stats(nla_data(attr), sp);
return 0;
}
struct rtnl_link_stats64 *dev_get_stats(struct net_device *dev,
struct rtnl_link_stats64 *storage)
{
...
storage->rx_nohandler += (unsigned long)atomic_long_read(&dev->rx_nohandler);
....
}
static void copy_rtnl_link_stats(struct rtnl_link_stats *a,
const struct rtnl_link_stats64 *b)
{
...
a->rx_nohandler = b->rx_nohandler;
}
rtnl_link_stats.rx_nohandler and rtnl_link_stats64.rx_nohandler
introduce by linux commit v4.5-rc2-193-g6e7333d.
>
> > + else if (!umove_or_printaddr(tcp, addr, &st)) {
> > + PRINT_FIELD_U("{", st, rx_packets);
> > + PRINT_FIELD_U(", ", st, tx_packets);
> > + PRINT_FIELD_U(", ", st, rx_bytes);
> > + PRINT_FIELD_U(", ", st, tx_bytes);
> > + PRINT_FIELD_U(", ", st, rx_errors);
> > + PRINT_FIELD_U(", ", st, tx_errors);
> > + PRINT_FIELD_U(", ", st, rx_dropped);
> > + PRINT_FIELD_U(", ", st, tx_dropped);
> > + PRINT_FIELD_U(", ", st, multicast);
> > + PRINT_FIELD_U(", ", st, collisions);
> > +
> > + PRINT_FIELD_U(", ", st, rx_length_errors);
> > + PRINT_FIELD_U(", ", st, rx_over_errors);
> > + PRINT_FIELD_U(", ", st, rx_crc_errors);
> > + PRINT_FIELD_U(", ", st, rx_frame_errors);
> > + PRINT_FIELD_U(", ", st, rx_fifo_errors);
> > + PRINT_FIELD_U(", ", st, rx_missed_errors);
> > +
> > + PRINT_FIELD_U(", ", st, tx_aborted_errors);
> > + PRINT_FIELD_U(", ", st, tx_carrier_errors);
> > + PRINT_FIELD_U(", ", st, tx_fifo_errors);
> > + PRINT_FIELD_U(", ", st, tx_heartbeat_errors);
> > + PRINT_FIELD_U(", ", st, tx_window_errors);
> > +
> > + PRINT_FIELD_U(", ", st, rx_compressed);
> > + PRINT_FIELD_U(", ", st, tx_compressed);
> > +#ifdef HAVE_STRUCT_RTNL_LINK_STATS_RX_NOHANDLER
> > + PRINT_FIELD_U(", ", st, rx_nohandler);
> > +#endif
> > + tprints("}");
> > + }
> > +
> > + return true;
> > +}
> > +
> > +static bool
> > +decode_rtnl_link_ifmap(struct tcb *const tcp,
> > + const kernel_ulong_t addr,
> > + const unsigned int len,
> > + const void *const opaque_data)
> > +{
> > + struct rtnl_link_ifmap map;
> > + const unsigned int sizeof_ifmap =
> > + offsetofend(struct rtnl_link_ifmap, port);
> > +
> > + if (len < sizeof_ifmap)
> > + return false;
> > + else if (!umoven_or_printaddr(tcp, addr, sizeof_ifmap, &map)) {
> > + PRINT_FIELD_X("{", map, mem_start);
> > + PRINT_FIELD_X(", ", map, mem_end);
> > + PRINT_FIELD_X(", ", map, base_addr);
> > + PRINT_FIELD_U(", ", map, irq);
> > + PRINT_FIELD_U(", ", map, dma);
> > + PRINT_FIELD_U(", ", map, port);
> > + tprints("}");
> > + }
> > +
> > + return true;
> > +}
> > +
> > +static bool
> > +decode_rtnl_link_stats64(struct tcb *const tcp,
> > + const kernel_ulong_t addr,
> > + const unsigned int len,
> > + const void *const opaque_data)
> > +{
> > +#ifdef HAVE_STRUCT_RTNL_LINK_STATS64
> > + struct rtnl_link_stats64 st;
> > +
> > + if (len < sizeof(st))
> > + return false;
> > + else if (!umove_or_printaddr(tcp, addr, &st)) {
> > + PRINT_FIELD_U("{", st, rx_packets);
> > + PRINT_FIELD_U(", ", st, tx_packets);
> > + PRINT_FIELD_U(", ", st, rx_bytes);
> > + PRINT_FIELD_U(", ", st, tx_bytes);
> > + PRINT_FIELD_U(", ", st, rx_errors);
> > + PRINT_FIELD_U(", ", st, tx_errors);
> > + PRINT_FIELD_U(", ", st, rx_dropped);
> > + PRINT_FIELD_U(", ", st, tx_dropped);
> > + PRINT_FIELD_U(", ", st, multicast);
> > + PRINT_FIELD_U(", ", st, collisions);
> > +
> > + PRINT_FIELD_U(", ", st, rx_length_errors);
> > + PRINT_FIELD_U(", ", st, rx_over_errors);
> > + PRINT_FIELD_U(", ", st, rx_crc_errors);
> > + PRINT_FIELD_U(", ", st, rx_frame_errors);
> > + PRINT_FIELD_U(", ", st, rx_fifo_errors);
> > + PRINT_FIELD_U(", ", st, rx_missed_errors);
> > +
> > + PRINT_FIELD_U(", ", st, tx_aborted_errors);
> > + PRINT_FIELD_U(", ", st, tx_carrier_errors);
> > + PRINT_FIELD_U(", ", st, tx_fifo_errors);
> > + PRINT_FIELD_U(", ", st, tx_heartbeat_errors);
> > + PRINT_FIELD_U(", ", st, tx_window_errors);
> > +
> > + PRINT_FIELD_U(", ", st, rx_compressed);
> > + PRINT_FIELD_U(", ", st, tx_compressed);
> > +#ifdef HAVE_STRUCT_RTNL_LINK_STATS64_RX_NOHANDLER
> > + PRINT_FIELD_U(", ", st, rx_nohandler);
> > +#endif
> > + tprints("}");
> > + }
> > +
> > + return true;
> > +#else
> > + return false;
> > +#endif
> > +}
> > +
> > +static bool
> > +print_item_id(struct tcb *const tcp, void *const elem_buf,
> > + const size_t elem_size, void *const opaque_data)
> > +{
> > + unsigned int *const count = opaque_data;
> > +
> > + /* MAX_PHYS_ITEM_ID_LEN = 32 */
> > + if ((*count)++ >= 32) {
> > + tprints("...");
> > + return false;
> > + }
> > +
> > + tprintf("%" PRIu8, *(uint8_t *) elem_buf);
I changed:
tprintf("%02x", *(uint8_t *) elem_buf);
> > +
> > + return true;
> > +}
> > +
> > +static bool
> > +decode_ifla_phys_item_id(struct tcb *const tcp,
> > + const kernel_ulong_t addr,
> > + const unsigned int len,
> > + const void *const opaque_data)
> > +{
> > + uint8_t id;
> > + unsigned int count = 0;
> > +
> > + print_array(tcp, addr, len, &id, sizeof(id),
> > + umoven_or_printaddr, print_item_id, &count);
>
> I'm not sure it's the best way to decode struct netdev_phys_item_id.id.
Or I can reference iproute2/lib/utils.c: hexstring_n2a
Now: [xx, xx, xx, xx, xx]
hexstring_n2a: xx xx xx xx xx xx
strace print xx xx xx xx xx xx seems strange, here space as delimiter,
easy to misunderstand it is in memory.
what do think?
>
> > +
> > + return true;
> > +}
> > +
> > +static const nla_decoder_t ifinfomsg_nla_decoders[] = {
> > + [IFLA_ADDRESS] = decode_ifla_address,
> > + [IFLA_BROADCAST] = decode_ifla_address,
> > + [IFLA_IFNAME] = decode_nla_str,
> > + [IFLA_MTU] = decode_nla_u32,
> > + [IFLA_LINK] = decode_nla_u32,
> > + [IFLA_QDISC] = decode_nla_str,
> > + [IFLA_STATS] = decode_rtnl_link_stats,
> > + [IFLA_COST] = NULL,
> > + [IFLA_PRIORITY] = NULL,
> > + [IFLA_MASTER] = decode_nla_u32,
> > + [IFLA_WIRELESS] = NULL,
>
> Here a parser of struct iw_event is expected.
>
> > + [IFLA_PROTINFO] = NULL,
>
> This one seems to be used in the kernel.
>
> > + [IFLA_TXQLEN] = decode_nla_u32,
> > + [IFLA_MAP] = decode_rtnl_link_ifmap,
> > + [IFLA_WEIGHT] = decode_nla_u32,
> > + [IFLA_OPERSTATE] = decode_nla_u8,
> > + [IFLA_LINKMODE] = decode_nla_u8,
> > + [IFLA_LINKINFO] = NULL,
>
> This one also seems to be used in the kernel.
>
> > + [IFLA_NET_NS_PID] = decode_nla_u32,
> > + [IFLA_IFALIAS] = decode_nla_str,
> > + [IFLA_NUM_VF] = decode_nla_u32,
> > + [IFLA_VFINFO_LIST] = NULL,
>
> Likewise.
>
> > + [IFLA_STATS64] = decode_rtnl_link_stats64,
> > + [IFLA_VF_PORTS] = NULL,
>
> Likewise.
>
> > + [IFLA_PORT_SELF] = NULL,
>
> Likewise.
>
> > + [IFLA_AF_SPEC] = NULL,
>
> Likewise.
>
> > + [IFLA_GROUP] = decode_nla_u32,
> > + [IFLA_NET_NS_FD] = decode_nla_u32,
> > + [IFLA_EXT_MASK] = decode_nla_u32,
> > + [IFLA_PROMISCUITY] = decode_nla_u32,
> > + [IFLA_NUM_TX_QUEUES] = decode_nla_u32,
> > + [IFLA_NUM_RX_QUEUES] = decode_nla_u32,
> > + [IFLA_CARRIER] = decode_nla_u8,
> > + [IFLA_PHYS_PORT_ID] = decode_ifla_phys_item_id,
> > + [IFLA_CARRIER_CHANGES] = decode_nla_u32,
> > + [IFLA_PHYS_SWITCH_ID] = decode_ifla_phys_item_id,
> > + [IFLA_LINK_NETNSID] = decode_nla_s32,
> > + [IFLA_PHYS_PORT_NAME] = decode_nla_str,
> > + [IFLA_PROTO_DOWN] = decode_nla_u8,
> > + [IFLA_GSO_MAX_SEGS] = decode_nla_u32,
> > + [IFLA_GSO_MAX_SIZE] = decode_nla_u32,
> > + [IFLA_PAD] = NULL,
> > + [IFLA_XDP] = NULL,
>
> Likewise.
You means that I should decode all the attributes?
Decode all the attributes in one commit the patch will very big,
and I'm not familiar with some attribute data, e.g. struct iw_event.
So need a lot of time.
--
JingPiao Chen
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