bpf: decode BPF_PROG_QUERY command
BPF_PROG_QUERY was introduced in Linux commit v4.15-rc1~84^2~558^2~6. * xlat/bpf_commands.in (BPF_PROG_QUERY): New constant. * xlat/bpf_query_flags.in: New file. * bpf.c: Include it. (DECL_BPF_CMD_DECODER): Add priv argument for passing tcb private data. (BEGIN_BPF_CMD_DECODER(BPF_PROG_QUERY)): New function. (SYS_FUNC(bpf)) <bpf_cmd_decoders>: Add BPF_PROG_QUERY entry. (SYS_FUNC(bpf)): Fetch buf on entering and exiting, pass buf on exiting, retrieve private data on exiting, pass it to decoder as well, explicitly rework rc handling logic for size argument printing. * bpf_attr.h (struct BPF_PROG_QUERY_struct): New structure declaration. (BPF_PROG_QUERY_struct_size, expected_BPF_PROG_QUERY_struct_size): New macro. * tests/bpf.c: Add checks for BPF_PROG_QUERY command.
This commit is contained in:
Eugene Syromyatnikov
parent
459ea39686
commit
39f61ef513
97
bpf.c
97
bpf.c
@ -45,13 +45,21 @@
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#include "xlat/bpf_map_update_elem_flags.h"
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#include "xlat/bpf_attach_type.h"
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#include "xlat/bpf_attach_flags.h"
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#include "xlat/bpf_query_flags.h"
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/** Storage for all the data that is needed to be stored on entering. */
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struct bpf_priv_data {
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bool bpf_prog_query_stored;
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uint32_t bpf_prog_query_prog_cnt;
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};
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#define DECL_BPF_CMD_DECODER(bpf_cmd_decoder) \
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int \
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bpf_cmd_decoder(struct tcb *const tcp, \
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const kernel_ulong_t addr, \
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const unsigned int size, \
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void *const data) \
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void *const data, \
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struct bpf_priv_data *priv) \
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/* End of DECL_BPF_CMD_DECODER definition. */
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#define BEGIN_BPF_CMD_DECODER(bpf_cmd) \
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@ -313,6 +321,53 @@ BEGIN_BPF_CMD_DECODER(BPF_OBJ_GET_INFO_BY_FD)
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}
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END_BPF_CMD_DECODER(RVAL_DECODED | RVAL_FD)
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BEGIN_BPF_CMD_DECODER(BPF_PROG_QUERY)
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{
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uint64_t prog_id_buf;
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if (entering(tcp)) {
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PRINT_FIELD_FD("{query={", attr, target_fd, tcp);
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PRINT_FIELD_XVAL(", ", attr, attach_type, bpf_attach_type,
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"BPF_???");
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PRINT_FIELD_FLAGS(", ", attr, query_flags, bpf_query_flags,
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"BPF_F_QUERY_???");
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PRINT_FIELD_FLAGS(", ", attr, attach_flags, bpf_attach_flags,
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"BPF_F_???");
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tprints(", prog_ids=");
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if (!priv)
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priv = xcalloc(1, sizeof(*priv));
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priv->bpf_prog_query_stored = true;
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priv->bpf_prog_query_prog_cnt = attr.prog_cnt;
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set_tcb_priv_data(tcp, priv, free);
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return 0;
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}
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/*
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* The issue here is that we can't pass pointers bigger than
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* (our) kernel long ti print_array, so we opt out from decoding
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* the array.
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*/
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if (syserror(tcp) || attr.prog_ids > max_kaddr())
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printaddr64(attr.prog_ids);
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else
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print_array(tcp, attr.prog_ids, attr.prog_cnt, &prog_id_buf,
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sizeof(prog_id_buf), umoven_or_printaddr,
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print_uint64_array_member, 0);
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tprints(", prog_cnt=");
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if (priv && priv->bpf_prog_query_stored
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&& priv->bpf_prog_query_prog_cnt != attr.prog_cnt)
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tprintf("%" PRIu32 " => ", priv->bpf_prog_query_prog_cnt);
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tprintf("%" PRIu32, attr.prog_cnt);
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tprints("}");
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}
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END_BPF_CMD_DECODER(RVAL_DECODED)
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SYS_FUNC(bpf)
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{
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static const bpf_cmd_decoder_t bpf_cmd_decoders[] = {
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@ -332,38 +387,38 @@ SYS_FUNC(bpf)
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BPF_CMD_ENTRY(BPF_PROG_GET_FD_BY_ID),
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BPF_CMD_ENTRY(BPF_MAP_GET_FD_BY_ID),
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BPF_CMD_ENTRY(BPF_OBJ_GET_INFO_BY_FD),
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BPF_CMD_ENTRY(BPF_PROG_QUERY),
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};
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static char *buf;
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struct bpf_priv_data *priv = NULL;
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const unsigned int cmd = tcp->u_arg[0];
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const kernel_ulong_t addr = tcp->u_arg[1];
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const unsigned int size = tcp->u_arg[2];
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int rc;
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int rc = RVAL_DECODED;
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if (!buf)
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buf = xmalloc(get_pagesize());
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if (entering(tcp)) {
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static char *buf;
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if (!buf)
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buf = xmalloc(get_pagesize());
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printxval(bpf_commands, cmd, "BPF_???");
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tprints(", ");
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if (size > 0
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&& size <= get_pagesize()
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&& cmd < ARRAY_SIZE(bpf_cmd_decoders)
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&& bpf_cmd_decoders[cmd]) {
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rc = umoven_or_printaddr(tcp, addr, size, buf)
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? RVAL_DECODED
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: bpf_cmd_decoders[cmd](tcp, addr, size, buf);
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} else {
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printaddr(addr);
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rc = RVAL_DECODED;
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}
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} else {
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rc = bpf_cmd_decoders[cmd](tcp, addr, size, NULL) | RVAL_DECODED;
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priv = get_tcb_priv_data(tcp);
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}
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if (rc & RVAL_DECODED)
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if (size > 0
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&& size <= get_pagesize()
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&& cmd < ARRAY_SIZE(bpf_cmd_decoders)
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&& bpf_cmd_decoders[cmd]) {
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if (!umoven_or_printaddr_ignore_syserror(tcp, addr, size, buf))
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rc = bpf_cmd_decoders[cmd](tcp, addr, size, buf, priv);
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} else {
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printaddr(addr);
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}
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if (exiting(tcp) || (rc & RVAL_DECODED))
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tprintf(", %u", size);
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return rc;
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13
bpf_attr.h
13
bpf_attr.h
@ -200,4 +200,17 @@ struct BPF_OBJ_GET_INFO_BY_FD_struct /* info */ {
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sizeof(struct BPF_OBJ_GET_INFO_BY_FD_struct)
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#define expected_BPF_OBJ_GET_INFO_BY_FD_struct_size 16
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struct BPF_PROG_QUERY_struct /* query */ {
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uint32_t target_fd;
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uint32_t attach_type;
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uint32_t query_flags;
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uint32_t attach_flags;
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uint64_t ATTRIBUTE_ALIGNED(8) prog_ids;
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uint32_t prog_cnt;
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};
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#define BPF_PROG_QUERY_struct_size \
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offsetofend(struct BPF_PROG_QUERY_struct, prog_cnt)
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#define expected_BPF_PROG_QUERY_struct_size 28
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#endif /* !STRACE_BPF_ATTR_H */
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61
tests/bpf.c
61
tests/bpf.c
@ -76,6 +76,7 @@ union bpf_attr_data {
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BPF_ATTR_DATA_FIELD(BPF_PROG_GET_FD_BY_ID);
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BPF_ATTR_DATA_FIELD(BPF_MAP_GET_FD_BY_ID);
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BPF_ATTR_DATA_FIELD(BPF_OBJ_GET_INFO_BY_FD);
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BPF_ATTR_DATA_FIELD(BPF_PROG_QUERY);
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char char_data[256];
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};
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@ -697,6 +698,65 @@ static const struct bpf_attr_check BPF_OBJ_GET_INFO_BY_FD_checks[] = {
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}
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};
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/* TODO: This is a read/write cmd and we do not check exiting path yet */
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static const struct bpf_attr_check BPF_PROG_QUERY_checks[] = {
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{
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.data = { .BPF_PROG_QUERY_data = { .target_fd = -1 } },
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.size = offsetofend(struct BPF_PROG_QUERY_struct, target_fd),
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.str = "query={target_fd=-1"
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", attach_type=BPF_CGROUP_INET_INGRESS, query_flags=0"
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", attach_flags=0, prog_ids=NULL, prog_cnt=0}",
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},
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{ /* 1 */
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.data = { .BPF_PROG_QUERY_data = {
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.target_fd = 3141592653U,
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.attach_type = 6,
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.query_flags = 1,
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.attach_flags = 3,
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} },
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.size = offsetofend(struct BPF_PROG_QUERY_struct, attach_flags),
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.str = "query={target_fd=-1153374643"
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", attach_type=BPF_CGROUP_DEVICE"
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", query_flags=BPF_F_QUERY_EFFECTIVE"
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", attach_flags=BPF_F_ALLOW_OVERRIDE|BPF_F_ALLOW_MULTI"
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", prog_ids=NULL, prog_cnt=0}",
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},
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{ /* 2 */
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.data = { .BPF_PROG_QUERY_data = {
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.target_fd = 3141592653U,
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.attach_type = 7,
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.query_flags = 0xfffffffe,
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.attach_flags = 0xfffffffc,
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.prog_ids = 0xffffffffffffffffULL,
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.prog_cnt = 2718281828,
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} },
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.size = offsetofend(struct BPF_PROG_QUERY_struct, prog_cnt),
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.str = "query={target_fd=-1153374643"
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", attach_type=0x7 /* BPF_??? */"
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", query_flags=0xfffffffe /* BPF_F_QUERY_??? */"
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", attach_flags=0xfffffffc /* BPF_F_??? */"
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", prog_ids=0xffffffffffffffff, prog_cnt=2718281828}",
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},
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{ /* 3 */
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.data = { .BPF_PROG_QUERY_data = {
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.target_fd = 3141592653U,
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.attach_type = 0xfeedface,
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.query_flags = 0xdeadf00d,
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.attach_flags = 0xbeefcafe,
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.prog_ids = 0xffffffffffffffffULL,
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.prog_cnt = 0,
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} },
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.size = offsetofend(struct BPF_PROG_QUERY_struct, prog_cnt),
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.str = "query={target_fd=-1153374643"
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", attach_type=0xfeedface /* BPF_??? */"
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", query_flags=BPF_F_QUERY_EFFECTIVE|0xdeadf00c"
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", attach_flags=BPF_F_ALLOW_MULTI|0xbeefcafc"
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", prog_ids=0xffffffffffffffff, prog_cnt=0}",
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},
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};
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#define CHK(cmd_) \
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{ \
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cmd_, #cmd_, \
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@ -724,6 +784,7 @@ main(void)
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CHK(BPF_PROG_GET_FD_BY_ID),
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CHK(BPF_MAP_GET_FD_BY_ID),
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CHK(BPF_OBJ_GET_INFO_BY_FD),
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CHK(BPF_PROG_QUERY),
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};
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page_size = get_page_size();
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@ -14,3 +14,4 @@ BPF_MAP_GET_NEXT_ID 12
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BPF_PROG_GET_FD_BY_ID 13
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BPF_MAP_GET_FD_BY_ID 14
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BPF_OBJ_GET_INFO_BY_FD 15
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BPF_PROG_QUERY 16
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1
xlat/bpf_query_flags.in
Normal file
1
xlat/bpf_query_flags.in
Normal file
@ -0,0 +1 @@
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BPF_F_QUERY_EFFECTIVE (1U << 0)
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