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bpf: Refactor sock_ops_convert_ctx_access
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The next patch will introduce a new "struct bpf_tcp_sock" which
exposes the same tcp_sock's fields already exposed in
"struct bpf_sock_ops".

This patch refactor the existing convert_ctx_access() codes for
"struct bpf_sock_ops" to get them ready to be reused for
"struct bpf_tcp_sock".  The "rtt_min" is not refactored
in this patch because its handling is different from other
fields.

The SOCK_OPS_GET_TCP_SOCK_FIELD is new. All other SOCK_OPS_XXX_FIELD
changes are code move only.

Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Martin KaFai Lau authored and Alexei Starovoitov committed Feb 11, 2019
1 parent aa65d69 commit 9b1f3d6
Showing 1 changed file with 127 additions and 160 deletions.
287 changes: 127 additions & 160 deletions net/core/filter.c
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Original file line number Diff line number Diff line change
Expand Up @@ -5030,6 +5030,54 @@ static const struct bpf_func_proto bpf_lwt_seg6_adjust_srh_proto = {
};
#endif /* CONFIG_IPV6_SEG6_BPF */

#define CONVERT_COMMON_TCP_SOCK_FIELDS(md_type, CONVERT) \
do { \
switch (si->off) { \
case offsetof(md_type, snd_cwnd): \
CONVERT(snd_cwnd); break; \
case offsetof(md_type, srtt_us): \
CONVERT(srtt_us); break; \
case offsetof(md_type, snd_ssthresh): \
CONVERT(snd_ssthresh); break; \
case offsetof(md_type, rcv_nxt): \
CONVERT(rcv_nxt); break; \
case offsetof(md_type, snd_nxt): \
CONVERT(snd_nxt); break; \
case offsetof(md_type, snd_una): \
CONVERT(snd_una); break; \
case offsetof(md_type, mss_cache): \
CONVERT(mss_cache); break; \
case offsetof(md_type, ecn_flags): \
CONVERT(ecn_flags); break; \
case offsetof(md_type, rate_delivered): \
CONVERT(rate_delivered); break; \
case offsetof(md_type, rate_interval_us): \
CONVERT(rate_interval_us); break; \
case offsetof(md_type, packets_out): \
CONVERT(packets_out); break; \
case offsetof(md_type, retrans_out): \
CONVERT(retrans_out); break; \
case offsetof(md_type, total_retrans): \
CONVERT(total_retrans); break; \
case offsetof(md_type, segs_in): \
CONVERT(segs_in); break; \
case offsetof(md_type, data_segs_in): \
CONVERT(data_segs_in); break; \
case offsetof(md_type, segs_out): \
CONVERT(segs_out); break; \
case offsetof(md_type, data_segs_out): \
CONVERT(data_segs_out); break; \
case offsetof(md_type, lost_out): \
CONVERT(lost_out); break; \
case offsetof(md_type, sacked_out): \
CONVERT(sacked_out); break; \
case offsetof(md_type, bytes_received): \
CONVERT(bytes_received); break; \
case offsetof(md_type, bytes_acked): \
CONVERT(bytes_acked); break; \
} \
} while (0)

#ifdef CONFIG_INET
static struct sock *sk_lookup(struct net *net, struct bpf_sock_tuple *tuple,
int dif, int sdif, u8 family, u8 proto)
Expand Down Expand Up @@ -7196,6 +7244,85 @@ static u32 sock_ops_convert_ctx_access(enum bpf_access_type type,
struct bpf_insn *insn = insn_buf;
int off;

/* Helper macro for adding read access to tcp_sock or sock fields. */
#define SOCK_OPS_GET_FIELD(BPF_FIELD, OBJ_FIELD, OBJ) \
do { \
BUILD_BUG_ON(FIELD_SIZEOF(OBJ, OBJ_FIELD) > \
FIELD_SIZEOF(struct bpf_sock_ops, BPF_FIELD)); \
*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF( \
struct bpf_sock_ops_kern, \
is_fullsock), \
si->dst_reg, si->src_reg, \
offsetof(struct bpf_sock_ops_kern, \
is_fullsock)); \
*insn++ = BPF_JMP_IMM(BPF_JEQ, si->dst_reg, 0, 2); \
*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF( \
struct bpf_sock_ops_kern, sk),\
si->dst_reg, si->src_reg, \
offsetof(struct bpf_sock_ops_kern, sk));\
*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(OBJ, \
OBJ_FIELD), \
si->dst_reg, si->dst_reg, \
offsetof(OBJ, OBJ_FIELD)); \
} while (0)

#define SOCK_OPS_GET_TCP_SOCK_FIELD(FIELD) \
SOCK_OPS_GET_FIELD(FIELD, FIELD, struct tcp_sock)

/* Helper macro for adding write access to tcp_sock or sock fields.
* The macro is called with two registers, dst_reg which contains a pointer
* to ctx (context) and src_reg which contains the value that should be
* stored. However, we need an additional register since we cannot overwrite
* dst_reg because it may be used later in the program.
* Instead we "borrow" one of the other register. We first save its value
* into a new (temp) field in bpf_sock_ops_kern, use it, and then restore
* it at the end of the macro.
*/
#define SOCK_OPS_SET_FIELD(BPF_FIELD, OBJ_FIELD, OBJ) \
do { \
int reg = BPF_REG_9; \
BUILD_BUG_ON(FIELD_SIZEOF(OBJ, OBJ_FIELD) > \
FIELD_SIZEOF(struct bpf_sock_ops, BPF_FIELD)); \
if (si->dst_reg == reg || si->src_reg == reg) \
reg--; \
if (si->dst_reg == reg || si->src_reg == reg) \
reg--; \
*insn++ = BPF_STX_MEM(BPF_DW, si->dst_reg, reg, \
offsetof(struct bpf_sock_ops_kern, \
temp)); \
*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF( \
struct bpf_sock_ops_kern, \
is_fullsock), \
reg, si->dst_reg, \
offsetof(struct bpf_sock_ops_kern, \
is_fullsock)); \
*insn++ = BPF_JMP_IMM(BPF_JEQ, reg, 0, 2); \
*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF( \
struct bpf_sock_ops_kern, sk),\
reg, si->dst_reg, \
offsetof(struct bpf_sock_ops_kern, sk));\
*insn++ = BPF_STX_MEM(BPF_FIELD_SIZEOF(OBJ, OBJ_FIELD), \
reg, si->src_reg, \
offsetof(OBJ, OBJ_FIELD)); \
*insn++ = BPF_LDX_MEM(BPF_DW, reg, si->dst_reg, \
offsetof(struct bpf_sock_ops_kern, \
temp)); \
} while (0)

#define SOCK_OPS_GET_OR_SET_FIELD(BPF_FIELD, OBJ_FIELD, OBJ, TYPE) \
do { \
if (TYPE == BPF_WRITE) \
SOCK_OPS_SET_FIELD(BPF_FIELD, OBJ_FIELD, OBJ); \
else \
SOCK_OPS_GET_FIELD(BPF_FIELD, OBJ_FIELD, OBJ); \
} while (0)

CONVERT_COMMON_TCP_SOCK_FIELDS(struct bpf_sock_ops,
SOCK_OPS_GET_TCP_SOCK_FIELD);

if (insn > insn_buf)
return insn - insn_buf;

switch (si->off) {
case offsetof(struct bpf_sock_ops, op) ...
offsetof(struct bpf_sock_ops, replylong[3]):
Expand Down Expand Up @@ -7353,175 +7480,15 @@ static u32 sock_ops_convert_ctx_access(enum bpf_access_type type,
FIELD_SIZEOF(struct minmax_sample, t));
break;

/* Helper macro for adding read access to tcp_sock or sock fields. */
#define SOCK_OPS_GET_FIELD(BPF_FIELD, OBJ_FIELD, OBJ) \
do { \
BUILD_BUG_ON(FIELD_SIZEOF(OBJ, OBJ_FIELD) > \
FIELD_SIZEOF(struct bpf_sock_ops, BPF_FIELD)); \
*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF( \
struct bpf_sock_ops_kern, \
is_fullsock), \
si->dst_reg, si->src_reg, \
offsetof(struct bpf_sock_ops_kern, \
is_fullsock)); \
*insn++ = BPF_JMP_IMM(BPF_JEQ, si->dst_reg, 0, 2); \
*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF( \
struct bpf_sock_ops_kern, sk),\
si->dst_reg, si->src_reg, \
offsetof(struct bpf_sock_ops_kern, sk));\
*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(OBJ, \
OBJ_FIELD), \
si->dst_reg, si->dst_reg, \
offsetof(OBJ, OBJ_FIELD)); \
} while (0)

/* Helper macro for adding write access to tcp_sock or sock fields.
* The macro is called with two registers, dst_reg which contains a pointer
* to ctx (context) and src_reg which contains the value that should be
* stored. However, we need an additional register since we cannot overwrite
* dst_reg because it may be used later in the program.
* Instead we "borrow" one of the other register. We first save its value
* into a new (temp) field in bpf_sock_ops_kern, use it, and then restore
* it at the end of the macro.
*/
#define SOCK_OPS_SET_FIELD(BPF_FIELD, OBJ_FIELD, OBJ) \
do { \
int reg = BPF_REG_9; \
BUILD_BUG_ON(FIELD_SIZEOF(OBJ, OBJ_FIELD) > \
FIELD_SIZEOF(struct bpf_sock_ops, BPF_FIELD)); \
if (si->dst_reg == reg || si->src_reg == reg) \
reg--; \
if (si->dst_reg == reg || si->src_reg == reg) \
reg--; \
*insn++ = BPF_STX_MEM(BPF_DW, si->dst_reg, reg, \
offsetof(struct bpf_sock_ops_kern, \
temp)); \
*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF( \
struct bpf_sock_ops_kern, \
is_fullsock), \
reg, si->dst_reg, \
offsetof(struct bpf_sock_ops_kern, \
is_fullsock)); \
*insn++ = BPF_JMP_IMM(BPF_JEQ, reg, 0, 2); \
*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF( \
struct bpf_sock_ops_kern, sk),\
reg, si->dst_reg, \
offsetof(struct bpf_sock_ops_kern, sk));\
*insn++ = BPF_STX_MEM(BPF_FIELD_SIZEOF(OBJ, OBJ_FIELD), \
reg, si->src_reg, \
offsetof(OBJ, OBJ_FIELD)); \
*insn++ = BPF_LDX_MEM(BPF_DW, reg, si->dst_reg, \
offsetof(struct bpf_sock_ops_kern, \
temp)); \
} while (0)

#define SOCK_OPS_GET_OR_SET_FIELD(BPF_FIELD, OBJ_FIELD, OBJ, TYPE) \
do { \
if (TYPE == BPF_WRITE) \
SOCK_OPS_SET_FIELD(BPF_FIELD, OBJ_FIELD, OBJ); \
else \
SOCK_OPS_GET_FIELD(BPF_FIELD, OBJ_FIELD, OBJ); \
} while (0)

case offsetof(struct bpf_sock_ops, snd_cwnd):
SOCK_OPS_GET_FIELD(snd_cwnd, snd_cwnd, struct tcp_sock);
break;

case offsetof(struct bpf_sock_ops, srtt_us):
SOCK_OPS_GET_FIELD(srtt_us, srtt_us, struct tcp_sock);
break;

case offsetof(struct bpf_sock_ops, bpf_sock_ops_cb_flags):
SOCK_OPS_GET_FIELD(bpf_sock_ops_cb_flags, bpf_sock_ops_cb_flags,
struct tcp_sock);
break;

case offsetof(struct bpf_sock_ops, snd_ssthresh):
SOCK_OPS_GET_FIELD(snd_ssthresh, snd_ssthresh, struct tcp_sock);
break;

case offsetof(struct bpf_sock_ops, rcv_nxt):
SOCK_OPS_GET_FIELD(rcv_nxt, rcv_nxt, struct tcp_sock);
break;

case offsetof(struct bpf_sock_ops, snd_nxt):
SOCK_OPS_GET_FIELD(snd_nxt, snd_nxt, struct tcp_sock);
break;

case offsetof(struct bpf_sock_ops, snd_una):
SOCK_OPS_GET_FIELD(snd_una, snd_una, struct tcp_sock);
break;

case offsetof(struct bpf_sock_ops, mss_cache):
SOCK_OPS_GET_FIELD(mss_cache, mss_cache, struct tcp_sock);
break;

case offsetof(struct bpf_sock_ops, ecn_flags):
SOCK_OPS_GET_FIELD(ecn_flags, ecn_flags, struct tcp_sock);
break;

case offsetof(struct bpf_sock_ops, rate_delivered):
SOCK_OPS_GET_FIELD(rate_delivered, rate_delivered,
struct tcp_sock);
break;

case offsetof(struct bpf_sock_ops, rate_interval_us):
SOCK_OPS_GET_FIELD(rate_interval_us, rate_interval_us,
struct tcp_sock);
break;

case offsetof(struct bpf_sock_ops, packets_out):
SOCK_OPS_GET_FIELD(packets_out, packets_out, struct tcp_sock);
break;

case offsetof(struct bpf_sock_ops, retrans_out):
SOCK_OPS_GET_FIELD(retrans_out, retrans_out, struct tcp_sock);
break;

case offsetof(struct bpf_sock_ops, total_retrans):
SOCK_OPS_GET_FIELD(total_retrans, total_retrans,
struct tcp_sock);
break;

case offsetof(struct bpf_sock_ops, segs_in):
SOCK_OPS_GET_FIELD(segs_in, segs_in, struct tcp_sock);
break;

case offsetof(struct bpf_sock_ops, data_segs_in):
SOCK_OPS_GET_FIELD(data_segs_in, data_segs_in, struct tcp_sock);
break;

case offsetof(struct bpf_sock_ops, segs_out):
SOCK_OPS_GET_FIELD(segs_out, segs_out, struct tcp_sock);
break;

case offsetof(struct bpf_sock_ops, data_segs_out):
SOCK_OPS_GET_FIELD(data_segs_out, data_segs_out,
struct tcp_sock);
break;

case offsetof(struct bpf_sock_ops, lost_out):
SOCK_OPS_GET_FIELD(lost_out, lost_out, struct tcp_sock);
break;

case offsetof(struct bpf_sock_ops, sacked_out):
SOCK_OPS_GET_FIELD(sacked_out, sacked_out, struct tcp_sock);
break;

case offsetof(struct bpf_sock_ops, sk_txhash):
SOCK_OPS_GET_OR_SET_FIELD(sk_txhash, sk_txhash,
struct sock, type);
break;

case offsetof(struct bpf_sock_ops, bytes_received):
SOCK_OPS_GET_FIELD(bytes_received, bytes_received,
struct tcp_sock);
break;

case offsetof(struct bpf_sock_ops, bytes_acked):
SOCK_OPS_GET_FIELD(bytes_acked, bytes_acked, struct tcp_sock);
break;

}
return insn - insn_buf;
}
Expand Down

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