Mercurial > hg > nginx
annotate src/event/quic/bpf/ngx_quic_reuseport_helper.c @ 9196:6c8595b77e66
QUIC: path aware in-flight bytes accounting.
On-packet acknowledgement is made path aware, as per RFC 9000, Section 9.4:
Packets sent on the old path MUST NOT contribute to congestion control
or RTT estimation for the new path.
To make this possible in a single congestion control context, the first packet
to be sent after the new path has been validated, which includes resetting the
congestion controller and RTT estimator, is now remembered in the connection.
Packets sent previously, such as on the old path, are not taken into account.
Note that although the packet number is saved per-connection, the added checks
affect application level packets only. For non-application level packets,
which are only processed prior to the handshake is complete, the remembered
packet number remains set to zero.
| author | Sergey Kandaurov <pluknet@nginx.com> |
|---|---|
| date | Tue, 12 Dec 2023 20:21:12 +0400 |
| parents | a2fbae359828 |
| children |
| rev | line source |
|---|---|
| 8676 | 1 #include <errno.h> |
| 2 #include <linux/string.h> | |
| 3 #include <linux/udp.h> | |
| 4 #include <linux/bpf.h> | |
| 5 /* | |
| 6 * the bpf_helpers.h is not included into linux-headers, only available | |
| 7 * with kernel sources in "tools/lib/bpf/bpf_helpers.h" or in libbpf. | |
| 8 */ | |
| 9 #include <bpf/bpf_helpers.h> | |
| 10 | |
| 11 | |
| 12 #if !defined(SEC) | |
| 13 #define SEC(NAME) __attribute__((section(NAME), used)) | |
| 14 #endif | |
| 15 | |
| 16 | |
| 17 #if defined(LICENSE_GPL) | |
| 18 | |
| 19 /* | |
| 20 * To see debug: | |
| 21 * | |
| 22 * echo 1 > /sys/kernel/debug/tracing/events/bpf_trace/enable | |
| 23 * cat /sys/kernel/debug/tracing/trace_pipe | |
| 24 * echo 0 > /sys/kernel/debug/tracing/events/bpf_trace/enable | |
| 25 */ | |
| 26 | |
| 27 #define debugmsg(fmt, ...) \ | |
| 28 do { \ | |
| 29 char __buf[] = fmt; \ | |
| 30 bpf_trace_printk(__buf, sizeof(__buf), ##__VA_ARGS__); \ | |
| 31 } while (0) | |
| 32 | |
| 33 #else | |
| 34 | |
| 35 #define debugmsg(fmt, ...) | |
| 36 | |
| 37 #endif | |
| 38 | |
| 39 char _license[] SEC("license") = LICENSE; | |
| 40 | |
| 41 /*****************************************************************************/ | |
| 42 | |
| 43 #define NGX_QUIC_PKT_LONG 0x80 /* header form */ | |
| 44 #define NGX_QUIC_SERVER_CID_LEN 20 | |
| 45 | |
| 46 | |
| 47 #define advance_data(nbytes) \ | |
| 48 offset += nbytes; \ | |
| 49 if (start + offset > end) { \ | |
| 50 debugmsg("cannot read %ld bytes at offset %ld", nbytes, offset); \ | |
| 51 goto failed; \ | |
| 52 } \ | |
| 53 data = start + offset - 1; | |
| 54 | |
| 55 | |
| 56 #define ngx_quic_parse_uint64(p) \ | |
| 57 (((__u64)(p)[0] << 56) | \ | |
| 58 ((__u64)(p)[1] << 48) | \ | |
| 59 ((__u64)(p)[2] << 40) | \ | |
| 60 ((__u64)(p)[3] << 32) | \ | |
|
8720
1a489587e1c8
QUIC: fixed key extraction in bpf.
Vladimir Homutov <vl@nginx.com>
parents:
8676
diff
changeset
|
61 ((__u64)(p)[4] << 24) | \ |
|
1a489587e1c8
QUIC: fixed key extraction in bpf.
Vladimir Homutov <vl@nginx.com>
parents:
8676
diff
changeset
|
62 ((__u64)(p)[5] << 16) | \ |
|
1a489587e1c8
QUIC: fixed key extraction in bpf.
Vladimir Homutov <vl@nginx.com>
parents:
8676
diff
changeset
|
63 ((__u64)(p)[6] << 8) | \ |
|
1a489587e1c8
QUIC: fixed key extraction in bpf.
Vladimir Homutov <vl@nginx.com>
parents:
8676
diff
changeset
|
64 ((__u64)(p)[7])) |
| 8676 | 65 |
| 66 /* | |
| 67 * actual map object is created by the "bpf" system call, | |
| 68 * all pointers to this variable are replaced by the bpf loader | |
| 69 */ | |
| 70 struct bpf_map_def SEC("maps") ngx_quic_sockmap; | |
| 71 | |
| 72 | |
| 73 SEC(PROGNAME) | |
| 74 int ngx_quic_select_socket_by_dcid(struct sk_reuseport_md *ctx) | |
| 75 { | |
| 76 int rc; | |
| 77 __u64 key; | |
| 78 size_t len, offset; | |
| 79 unsigned char *start, *end, *data, *dcid; | |
| 80 | |
| 81 start = ctx->data; | |
| 82 end = (unsigned char *) ctx->data_end; | |
| 83 offset = 0; | |
| 84 | |
|
8720
1a489587e1c8
QUIC: fixed key extraction in bpf.
Vladimir Homutov <vl@nginx.com>
parents:
8676
diff
changeset
|
85 advance_data(sizeof(struct udphdr)); /* data at UDP header */ |
|
1a489587e1c8
QUIC: fixed key extraction in bpf.
Vladimir Homutov <vl@nginx.com>
parents:
8676
diff
changeset
|
86 advance_data(1); /* data at QUIC flags */ |
| 8676 | 87 |
| 88 if (data[0] & NGX_QUIC_PKT_LONG) { | |
| 89 | |
|
8720
1a489587e1c8
QUIC: fixed key extraction in bpf.
Vladimir Homutov <vl@nginx.com>
parents:
8676
diff
changeset
|
90 advance_data(4); /* data at QUIC version */ |
|
1a489587e1c8
QUIC: fixed key extraction in bpf.
Vladimir Homutov <vl@nginx.com>
parents:
8676
diff
changeset
|
91 advance_data(1); /* data at DCID len */ |
|
1a489587e1c8
QUIC: fixed key extraction in bpf.
Vladimir Homutov <vl@nginx.com>
parents:
8676
diff
changeset
|
92 |
| 8676 | 93 len = data[0]; /* read DCID length */ |
| 94 | |
| 95 if (len < 8) { | |
| 96 /* it's useless to search for key in such short DCID */ | |
| 97 return SK_PASS; | |
| 98 } | |
| 99 | |
| 100 } else { | |
| 101 len = NGX_QUIC_SERVER_CID_LEN; | |
| 102 } | |
| 103 | |
| 104 dcid = &data[1]; | |
| 105 advance_data(len); /* we expect the packet to have full DCID */ | |
| 106 | |
| 107 /* make verifier happy */ | |
| 108 if (dcid + sizeof(__u64) > end) { | |
| 109 goto failed; | |
| 110 } | |
| 111 | |
| 112 key = ngx_quic_parse_uint64(dcid); | |
| 113 | |
| 114 rc = bpf_sk_select_reuseport(ctx, &ngx_quic_sockmap, &key, 0); | |
| 115 | |
| 116 switch (rc) { | |
| 117 case 0: | |
|
8720
1a489587e1c8
QUIC: fixed key extraction in bpf.
Vladimir Homutov <vl@nginx.com>
parents:
8676
diff
changeset
|
118 debugmsg("nginx quic socket selected by key 0x%llx", key); |
| 8676 | 119 return SK_PASS; |
| 120 | |
| 121 /* kernel returns positive error numbers, errno.h defines positive */ | |
| 122 case -ENOENT: | |
|
8720
1a489587e1c8
QUIC: fixed key extraction in bpf.
Vladimir Homutov <vl@nginx.com>
parents:
8676
diff
changeset
|
123 debugmsg("nginx quic default route for key 0x%llx", key); |
| 8676 | 124 /* let the default reuseport logic decide which socket to choose */ |
| 125 return SK_PASS; | |
| 126 | |
| 127 default: | |
|
8720
1a489587e1c8
QUIC: fixed key extraction in bpf.
Vladimir Homutov <vl@nginx.com>
parents:
8676
diff
changeset
|
128 debugmsg("nginx quic bpf_sk_select_reuseport err: %d key 0x%llx", |
|
9015
a2fbae359828
QUIC: fixed indentation.
Sergey Kandaurov <pluknet@nginx.com>
parents:
8720
diff
changeset
|
129 rc, key); |
| 8676 | 130 goto failed; |
| 131 } | |
| 132 | |
| 133 failed: | |
| 134 /* | |
| 135 * SK_DROP will generate ICMP, but we may want to process "invalid" packet | |
| 136 * in userspace quic to investigate further and finally react properly | |
| 137 * (maybe ignore, maybe send something in response or close connection) | |
| 138 */ | |
| 139 return SK_PASS; | |
| 140 } |