[PATCH v3 13/18] netlink: decode AF_PACKET packet_diag_msg attributes
Dmitry V. Levin
ldv at altlinux.org
Sat Jul 1 10:41:17 UTC 2017
On Wed, Jun 28, 2017 at 09:40:08AM +0800, JingPiao Chen wrote:
> * netlink_sock_diag.c: Include <linux/filter.h>
> and "xlat/packet_diag_info_flags.h".
> (packet_diag_msg_nla_decoders): New array.
> (decode_packet_diag_msg): Use it.
> * linux/packet_diag.h (packet_diag_info, packet_diag_mclist,
> packet_diag_ring): New structures.
> (PDI_*): New macros.
> * xlat/packet_diag_info_flags.in: New file.
> ---
> linux/packet_diag.h | 33 +++++++++++
> netlink_sock_diag.c | 126 ++++++++++++++++++++++++++++++++++++++++-
> xlat/packet_diag_info_flags.in | 5 ++
> 3 files changed, 163 insertions(+), 1 deletion(-)
> create mode 100644 xlat/packet_diag_info_flags.in
>
> diff --git a/linux/packet_diag.h b/linux/packet_diag.h
> index 3e8120b..368e26f 100644
> --- a/linux/packet_diag.h
> +++ b/linux/packet_diag.h
> @@ -37,4 +37,37 @@ enum {
> PACKET_DIAG_FILTER,
> };
>
> +struct packet_diag_info {
> + uint32_t pdi_index;
> + uint32_t pdi_version;
> + uint32_t pdi_reserve;
> + uint32_t pdi_copy_thresh;
> + uint32_t pdi_tstamp;
> + uint32_t pdi_flags;
> +
> +#define PDI_RUNNING 0x1
> +#define PDI_AUXDATA 0x2
> +#define PDI_ORIGDEV 0x4
> +#define PDI_VNETHDR 0x8
> +#define PDI_LOSS 0x10
> +};
> +
> +struct packet_diag_mclist {
> + uint32_t pdmc_index;
> + uint32_t pdmc_count;
> + uint16_t pdmc_type;
> + uint16_t pdmc_alen;
> + uint8_t pdmc_addr[32]; /* MAX_ADDR_LEN */
> +};
> +
> +struct packet_diag_ring {
> + uint32_t pdr_block_size;
> + uint32_t pdr_block_nr;
> + uint32_t pdr_frame_size;
> + uint32_t pdr_frame_nr;
> + uint32_t pdr_retire_tmo;
> + uint32_t pdr_sizeof_priv;
> + uint32_t pdr_features;
> +};
> +
> #endif /* !STRACE_LINUX_PACKET_DIAG_H */
> diff --git a/netlink_sock_diag.c b/netlink_sock_diag.c
> index f5b53b5..c0709c0 100644
> --- a/netlink_sock_diag.c
> +++ b/netlink_sock_diag.c
> @@ -32,6 +32,7 @@
> #include "nlattr.h"
>
> #include <arpa/inet.h>
> +#include <linux/filter.h>
<linux/filter.h> is not universally available yet, on other parts
of strace we wrap its use in #ifdef HAVE_LINUX_FILTER_H/#endif.
> #include <linux/inet_diag.h>
> #include <linux/netlink_diag.h>
> #include <linux/packet_diag.h>
> @@ -54,6 +55,7 @@
> #include "xlat/netlink_states.h"
>
> #include "xlat/packet_diag_attrs.h"
> +#include "xlat/packet_diag_info_flags.h"
> #include "xlat/packet_diag_show.h"
>
> #ifdef AF_SMC
> @@ -451,6 +453,127 @@ decode_packet_diag_req(struct tcb *const tcp,
> tprints("}");
> }
>
> +static bool
> +decode_packet_diag_info(struct tcb *tcp, kernel_ulong_t addr,
> + kernel_ulong_t len, const void *const opaque_data)
> +{
> + struct packet_diag_info pinfo;
> +
> + if (len < sizeof(pinfo))
> + return false;
> + if (umove_or_printaddr(tcp, addr, &pinfo))
> + return true;
> +
> + tprintf("{pdi_index=%" PRIu32 ", pdi_version=%" PRIu32
> + ", pdi_reserve=%" PRIu32 ", pdi_copy_thresh=%" PRIu32
> + ", pdi_tstamp=%" PRIu32 ", pdi_flags=",
> + pinfo.pdi_index, pinfo.pdi_version, pinfo.pdi_reserve,
> + pinfo.pdi_copy_thresh, pinfo.pdi_tstamp);
> + printflags(packet_diag_info_flags, pinfo.pdi_flags, "PDI_???");
> + tprints("}");
> +
> + return true;
> +}
> +
> +static bool
> +print_packet_diag_mclist(struct tcb *tcp, void *elem_buf,
> + size_t elem_size, void *opaque_data)
> +{
> + struct packet_diag_mclist *dml;
> +
> + dml = (struct packet_diag_mclist *) elem_buf;
> +
> + tprintf("{pdmc_index=%" PRIu32 ", pdmc_count=%" PRIu32
> + ", pdmc_type=%" PRIu16 ", pdmc_alen=%" PRIu16
> + ", pdmc_addr=",
> + dml->pdmc_index, dml->pdmc_count, dml->pdmc_type,
> + dml->pdmc_alen);
> + print_quoted_string((char *) dml->pdmc_addr, sizeof(dml->pdmc_addr),
> + QUOTE_0_TERMINATED);
I don't think packet_diag_mclist is printed properly here.
For example, pdmc_index seems to be an interface index we print using
print_ifindex; pdmc_addr is an address, not nul-terminated string, and
pdmc_alen is its actual length.
Please investigate what would be a correct representation of this
structure.
> + tprints("}");
> +
> + return true;
> +}
> +
> +static bool
> +decode_packet_diag_mclist(struct tcb *tcp, kernel_ulong_t addr,
> + kernel_ulong_t len, const void *const opaque_data)
> +{
> + struct packet_diag_mclist dml;
> + size_t nmemb = len / sizeof(dml);
> +
> + if (!nmemb)
> + return false;
> +
> + print_array(tcp, addr, nmemb, &dml, sizeof(dml),
> + umoven_or_printaddr, print_packet_diag_mclist, 0);
> +
> + return true;
> +}
> +
> +static bool
> +decode_packet_diag_ring(struct tcb *tcp, kernel_ulong_t addr,
> + kernel_ulong_t len, const void *const opaque_data)
> +{
> + struct packet_diag_ring pdr;
> +
> + if (len < sizeof(pdr))
> + return false;
> + if (umove_or_printaddr(tcp, addr, &pdr))
> + return true;
> +
> + tprintf("{pdr_block_size=%" PRIu32 ", pdr_block_nr=%" PRIu32
> + ", pdr_frame_size=%" PRIu32 ", pdr_frame_nr=%" PRIu32
> + ", pdr_retire_tmo=%" PRIu32 ", pdr_sizeof_priv=%" PRIu32
> + ", pdr_features=%" PRIu32 "}",
> + pdr.pdr_block_size, pdr.pdr_block_nr,
> + pdr.pdr_frame_size, pdr.pdr_frame_nr,
> + pdr.pdr_retire_tmo, pdr.pdr_sizeof_priv,
> + pdr.pdr_features);
> +
> + return true;
> +}
> +
> +static bool
> +print_sock_filter(struct tcb *tcp, void *elem_buf,
> + size_t elem_size, void *opaque_data)
> +{
> + struct sock_filter *filter = (struct sock_filter *)elem_buf;
No need to cast.
> + tprintf("{code=%" PRIu16 ", jt=%" PRIu8 ", jf=%" PRIu8 ", k=%" PRIu32,
> + filter->code, filter->jt, filter->jf, filter->k);
> + tprints("}");
> +
> + return true;
> +}
Note that this is a very primitive parser compared to print_bpf_filter
in seccomp.c.
> +
> +static bool
> +decode_sock_filter(struct tcb *tcp, kernel_ulong_t addr,
> + kernel_ulong_t len, const void *const opaque_data)
> +{
> + struct sock_filter filter;
> + size_t nmemb = len / sizeof(filter);
> +
> + if (!nmemb)
> + return false;
> +
> + print_array(tcp, addr, nmemb, &filter, sizeof(filter),
> + umoven_or_printaddr, print_sock_filter, 0);
> +
> + return true;
> +}
> +
> +static const nla_decoder_t packet_diag_msg_nla_decoders[] = {
> + [PACKET_DIAG_INFO] = decode_packet_diag_info,
> + [PACKET_DIAG_MCLIST] = decode_packet_diag_mclist,
> + [PACKET_DIAG_RX_RING] = decode_packet_diag_ring,
> + [PACKET_DIAG_TX_RING] = decode_packet_diag_ring,
> + [PACKET_DIAG_FANOUT] = decode_nla_u32,
> + [PACKET_DIAG_UID] = decode_nla_u32,
> + [PACKET_DIAG_MEMINFO] = decode_meminfo,
> + [PACKET_DIAG_FILTER] = decode_sock_filter
> +};
> +
> static void
> decode_packet_diag_msg(struct tcb *const tcp,
> const struct nlmsghdr *const nlmsghdr,
> @@ -487,7 +610,8 @@ decode_packet_diag_msg(struct tcb *const tcp,
> tprints(", ");
> decode_nlattr(tcp, addr + offset, len - offset,
> packet_diag_attrs, "PACKET_DIAG_???",
> - NULL, 0, NULL);
> + packet_diag_msg_nla_decoders,
> + ARRAY_SIZE(packet_diag_msg_nla_decoders), NULL);
> }
> }
>
> diff --git a/xlat/packet_diag_info_flags.in b/xlat/packet_diag_info_flags.in
> new file mode 100644
> index 0000000..30a47b1
> --- /dev/null
> +++ b/xlat/packet_diag_info_flags.in
> @@ -0,0 +1,5 @@
> +PDI_RUNNING 0x1
> +PDI_AUXDATA 0x2
> +PDI_ORIGDEV 0x4
> +PDI_VNETHDR 0x8
> +PDI_LOSS 0x10
These constants are defined in local linux/packet_diag.h already,
no fallback definitions are needed.
--
ldv
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