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nghttp2/bpf/reuseport_kern.c

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/*
* nghttp2 - HTTP/2 C Library
*
* Copyright (c) 2021 Tatsuhiro Tsujikawa
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
* LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
* OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
* WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
#include <linux/udp.h>
#include <linux/bpf.h>
#include <bpf/bpf_helpers.h>
/*
* How to compile:
*
* clang-12 -O2 -Wall -target bpf -g -c reuseport_kern.c -o reuseport_kern.o \
* -I/path/to/kernel/include
*
* See
* https://www.kernel.org/doc/Documentation/kbuild/headers_install.txt
* how to install kernel header files.
*/
/* AES_CBC_decrypt_buffer: https://github.com/kokke/tiny-AES-c
License is Public Domain. Commit hash:
12e7744b4919e9d55de75b7ab566326a1c8e7a67 */
#define AES_BLOCKLEN \
16 /* Block length in bytes - AES is 128b block \
only */
#define AES_KEYLEN 16 /* Key length in bytes */
#define AES_keyExpSize 176
struct AES_ctx {
__u8 RoundKey[AES_keyExpSize];
};
/* The number of columns comprising a state in AES. This is a constant
in AES. Value=4 */
#define Nb 4
#define Nk 4 /* The number of 32 bit words in a key. */
#define Nr 10 /* The number of rounds in AES Cipher. */
/* state - array holding the intermediate results during
decryption. */
typedef __u8 state_t[4][4];
/* The lookup-tables are marked const so they can be placed in
read-only storage instead of RAM The numbers below can be computed
dynamically trading ROM for RAM - This can be useful in (embedded)
bootloader applications, where ROM is often limited. */
static const __u8 sbox[256] = {
/* 0 1 2 3 4 5 6 7 8 9 A B C D E F */
0x63, 0x7c, 0x77, 0x7b, 0xf2, 0x6b, 0x6f, 0xc5, 0x30, 0x01, 0x67, 0x2b,
0xfe, 0xd7, 0xab, 0x76, 0xca, 0x82, 0xc9, 0x7d, 0xfa, 0x59, 0x47, 0xf0,
0xad, 0xd4, 0xa2, 0xaf, 0x9c, 0xa4, 0x72, 0xc0, 0xb7, 0xfd, 0x93, 0x26,
0x36, 0x3f, 0xf7, 0xcc, 0x34, 0xa5, 0xe5, 0xf1, 0x71, 0xd8, 0x31, 0x15,
0x04, 0xc7, 0x23, 0xc3, 0x18, 0x96, 0x05, 0x9a, 0x07, 0x12, 0x80, 0xe2,
0xeb, 0x27, 0xb2, 0x75, 0x09, 0x83, 0x2c, 0x1a, 0x1b, 0x6e, 0x5a, 0xa0,
0x52, 0x3b, 0xd6, 0xb3, 0x29, 0xe3, 0x2f, 0x84, 0x53, 0xd1, 0x00, 0xed,
0x20, 0xfc, 0xb1, 0x5b, 0x6a, 0xcb, 0xbe, 0x39, 0x4a, 0x4c, 0x58, 0xcf,
0xd0, 0xef, 0xaa, 0xfb, 0x43, 0x4d, 0x33, 0x85, 0x45, 0xf9, 0x02, 0x7f,
0x50, 0x3c, 0x9f, 0xa8, 0x51, 0xa3, 0x40, 0x8f, 0x92, 0x9d, 0x38, 0xf5,
0xbc, 0xb6, 0xda, 0x21, 0x10, 0xff, 0xf3, 0xd2, 0xcd, 0x0c, 0x13, 0xec,
0x5f, 0x97, 0x44, 0x17, 0xc4, 0xa7, 0x7e, 0x3d, 0x64, 0x5d, 0x19, 0x73,
0x60, 0x81, 0x4f, 0xdc, 0x22, 0x2a, 0x90, 0x88, 0x46, 0xee, 0xb8, 0x14,
0xde, 0x5e, 0x0b, 0xdb, 0xe0, 0x32, 0x3a, 0x0a, 0x49, 0x06, 0x24, 0x5c,
0xc2, 0xd3, 0xac, 0x62, 0x91, 0x95, 0xe4, 0x79, 0xe7, 0xc8, 0x37, 0x6d,
0x8d, 0xd5, 0x4e, 0xa9, 0x6c, 0x56, 0xf4, 0xea, 0x65, 0x7a, 0xae, 0x08,
0xba, 0x78, 0x25, 0x2e, 0x1c, 0xa6, 0xb4, 0xc6, 0xe8, 0xdd, 0x74, 0x1f,
0x4b, 0xbd, 0x8b, 0x8a, 0x70, 0x3e, 0xb5, 0x66, 0x48, 0x03, 0xf6, 0x0e,
0x61, 0x35, 0x57, 0xb9, 0x86, 0xc1, 0x1d, 0x9e, 0xe1, 0xf8, 0x98, 0x11,
0x69, 0xd9, 0x8e, 0x94, 0x9b, 0x1e, 0x87, 0xe9, 0xce, 0x55, 0x28, 0xdf,
0x8c, 0xa1, 0x89, 0x0d, 0xbf, 0xe6, 0x42, 0x68, 0x41, 0x99, 0x2d, 0x0f,
0xb0, 0x54, 0xbb, 0x16};
static const __u8 rsbox[256] = {
0x52, 0x09, 0x6a, 0xd5, 0x30, 0x36, 0xa5, 0x38, 0xbf, 0x40, 0xa3, 0x9e,
0x81, 0xf3, 0xd7, 0xfb, 0x7c, 0xe3, 0x39, 0x82, 0x9b, 0x2f, 0xff, 0x87,
0x34, 0x8e, 0x43, 0x44, 0xc4, 0xde, 0xe9, 0xcb, 0x54, 0x7b, 0x94, 0x32,
0xa6, 0xc2, 0x23, 0x3d, 0xee, 0x4c, 0x95, 0x0b, 0x42, 0xfa, 0xc3, 0x4e,
0x08, 0x2e, 0xa1, 0x66, 0x28, 0xd9, 0x24, 0xb2, 0x76, 0x5b, 0xa2, 0x49,
0x6d, 0x8b, 0xd1, 0x25, 0x72, 0xf8, 0xf6, 0x64, 0x86, 0x68, 0x98, 0x16,
0xd4, 0xa4, 0x5c, 0xcc, 0x5d, 0x65, 0xb6, 0x92, 0x6c, 0x70, 0x48, 0x50,
0xfd, 0xed, 0xb9, 0xda, 0x5e, 0x15, 0x46, 0x57, 0xa7, 0x8d, 0x9d, 0x84,
0x90, 0xd8, 0xab, 0x00, 0x8c, 0xbc, 0xd3, 0x0a, 0xf7, 0xe4, 0x58, 0x05,
0xb8, 0xb3, 0x45, 0x06, 0xd0, 0x2c, 0x1e, 0x8f, 0xca, 0x3f, 0x0f, 0x02,
0xc1, 0xaf, 0xbd, 0x03, 0x01, 0x13, 0x8a, 0x6b, 0x3a, 0x91, 0x11, 0x41,
0x4f, 0x67, 0xdc, 0xea, 0x97, 0xf2, 0xcf, 0xce, 0xf0, 0xb4, 0xe6, 0x73,
0x96, 0xac, 0x74, 0x22, 0xe7, 0xad, 0x35, 0x85, 0xe2, 0xf9, 0x37, 0xe8,
0x1c, 0x75, 0xdf, 0x6e, 0x47, 0xf1, 0x1a, 0x71, 0x1d, 0x29, 0xc5, 0x89,
0x6f, 0xb7, 0x62, 0x0e, 0xaa, 0x18, 0xbe, 0x1b, 0xfc, 0x56, 0x3e, 0x4b,
0xc6, 0xd2, 0x79, 0x20, 0x9a, 0xdb, 0xc0, 0xfe, 0x78, 0xcd, 0x5a, 0xf4,
0x1f, 0xdd, 0xa8, 0x33, 0x88, 0x07, 0xc7, 0x31, 0xb1, 0x12, 0x10, 0x59,
0x27, 0x80, 0xec, 0x5f, 0x60, 0x51, 0x7f, 0xa9, 0x19, 0xb5, 0x4a, 0x0d,
0x2d, 0xe5, 0x7a, 0x9f, 0x93, 0xc9, 0x9c, 0xef, 0xa0, 0xe0, 0x3b, 0x4d,
0xae, 0x2a, 0xf5, 0xb0, 0xc8, 0xeb, 0xbb, 0x3c, 0x83, 0x53, 0x99, 0x61,
0x17, 0x2b, 0x04, 0x7e, 0xba, 0x77, 0xd6, 0x26, 0xe1, 0x69, 0x14, 0x63,
0x55, 0x21, 0x0c, 0x7d};
/* The round constant word array, Rcon[i], contains the values given
by x to the power (i-1) being powers of x (x is denoted as {02}) in
the field GF(2^8) */
static const __u8 Rcon[11] = {0x8d, 0x01, 0x02, 0x04, 0x08, 0x10,
0x20, 0x40, 0x80, 0x1b, 0x36};
#define getSBoxValue(num) (sbox[(num)])
/* This function produces Nb(Nr+1) round keys. The round keys are used
in each round to decrypt the states. */
static void KeyExpansion(__u8 *RoundKey, const __u8 *Key) {
unsigned i, j, k;
__u8 tempa[4]; /* Used for the column/row operations */
/* The first round key is the key itself. */
for (i = 0; i < Nk; ++i) {
RoundKey[(i * 4) + 0] = Key[(i * 4) + 0];
RoundKey[(i * 4) + 1] = Key[(i * 4) + 1];
RoundKey[(i * 4) + 2] = Key[(i * 4) + 2];
RoundKey[(i * 4) + 3] = Key[(i * 4) + 3];
}
/* All other round keys are found from the previous round keys. */
for (i = Nk; i < Nb * (Nr + 1); ++i) {
{
k = (i - 1) * 4;
tempa[0] = RoundKey[k + 0];
tempa[1] = RoundKey[k + 1];
tempa[2] = RoundKey[k + 2];
tempa[3] = RoundKey[k + 3];
}
if (i % Nk == 0) {
/* This function shifts the 4 bytes in a word to the left once.
[a0,a1,a2,a3] becomes [a1,a2,a3,a0] */
/* Function RotWord() */
{
const __u8 u8tmp = tempa[0];
tempa[0] = tempa[1];
tempa[1] = tempa[2];
tempa[2] = tempa[3];
tempa[3] = u8tmp;
}
/* SubWord() is a function that takes a four-byte input word and
applies the S-box to each of the four bytes to produce an
output word. */
/* Function Subword() */
{
tempa[0] = getSBoxValue(tempa[0]);
tempa[1] = getSBoxValue(tempa[1]);
tempa[2] = getSBoxValue(tempa[2]);
tempa[3] = getSBoxValue(tempa[3]);
}
tempa[0] = tempa[0] ^ Rcon[i / Nk];
}
j = i * 4;
k = (i - Nk) * 4;
RoundKey[j + 0] = RoundKey[k + 0] ^ tempa[0];
RoundKey[j + 1] = RoundKey[k + 1] ^ tempa[1];
RoundKey[j + 2] = RoundKey[k + 2] ^ tempa[2];
RoundKey[j + 3] = RoundKey[k + 3] ^ tempa[3];
}
}
static void AES_init_ctx(struct AES_ctx *ctx, const __u8 *key) {
KeyExpansion(ctx->RoundKey, key);
}
/* This function adds the round key to state. The round key is added
to the state by an XOR function. */
static void AddRoundKey(__u8 round, state_t *state, const __u8 *RoundKey) {
__u8 i, j;
for (i = 0; i < 4; ++i) {
for (j = 0; j < 4; ++j) {
(*state)[i][j] ^= RoundKey[(round * Nb * 4) + (i * Nb) + j];
}
}
}
static __u8 xtime(__u8 x) { return ((x << 1) ^ (((x >> 7) & 1) * 0x1b)); }
#define Multiply(x, y) \
(((y & 1) * x) ^ ((y >> 1 & 1) * xtime(x)) ^ \
((y >> 2 & 1) * xtime(xtime(x))) ^ \
((y >> 3 & 1) * xtime(xtime(xtime(x)))) ^ \
((y >> 4 & 1) * xtime(xtime(xtime(xtime(x))))))
#define getSBoxInvert(num) (rsbox[(num)])
/* MixColumns function mixes the columns of the state matrix. The
method used to multiply may be difficult to understand for the
inexperienced. Please use the references to gain more
information. */
static void InvMixColumns(state_t *state) {
int i;
__u8 a, b, c, d;
for (i = 0; i < 4; ++i) {
a = (*state)[i][0];
b = (*state)[i][1];
c = (*state)[i][2];
d = (*state)[i][3];
(*state)[i][0] = Multiply(a, 0x0e) ^ Multiply(b, 0x0b) ^ Multiply(c, 0x0d) ^
Multiply(d, 0x09);
(*state)[i][1] = Multiply(a, 0x09) ^ Multiply(b, 0x0e) ^ Multiply(c, 0x0b) ^
Multiply(d, 0x0d);
(*state)[i][2] = Multiply(a, 0x0d) ^ Multiply(b, 0x09) ^ Multiply(c, 0x0e) ^
Multiply(d, 0x0b);
(*state)[i][3] = Multiply(a, 0x0b) ^ Multiply(b, 0x0d) ^ Multiply(c, 0x09) ^
Multiply(d, 0x0e);
}
}
extern __u32 LINUX_KERNEL_VERSION __kconfig;
/* The SubBytes Function Substitutes the values in the state matrix
with values in an S-box. */
static void InvSubBytes(state_t *state) {
__u8 i, j;
if (LINUX_KERNEL_VERSION < KERNEL_VERSION(5, 10, 0)) {
for (i = 0; i < 4; ++i) {
for (j = 0; j < 4; ++j) {
/* Ubuntu 20.04 LTS kernel 5.4.0 needs this workaround
otherwise "math between map_value pointer and register with
unbounded min value is not allowed". 5.10.0 is a kernel
version that works but it might not be the minimum
version. */
__u8 k = (*state)[j][i];
(*state)[j][i] = k ? getSBoxInvert(k) : getSBoxInvert(0);
}
}
} else {
for (i = 0; i < 4; ++i) {
for (j = 0; j < 4; ++j) {
(*state)[j][i] = getSBoxInvert((*state)[j][i]);
}
}
}
}
static void InvShiftRows(state_t *state) {
__u8 temp;
/* Rotate first row 1 columns to right */
temp = (*state)[3][1];
(*state)[3][1] = (*state)[2][1];
(*state)[2][1] = (*state)[1][1];
(*state)[1][1] = (*state)[0][1];
(*state)[0][1] = temp;
/* Rotate second row 2 columns to right */
temp = (*state)[0][2];
(*state)[0][2] = (*state)[2][2];
(*state)[2][2] = temp;
temp = (*state)[1][2];
(*state)[1][2] = (*state)[3][2];
(*state)[3][2] = temp;
/* Rotate third row 3 columns to right */
temp = (*state)[0][3];
(*state)[0][3] = (*state)[1][3];
(*state)[1][3] = (*state)[2][3];
(*state)[2][3] = (*state)[3][3];
(*state)[3][3] = temp;
}
static void InvCipher(state_t *state, const __u8 *RoundKey) {
/* Add the First round key to the state before starting the
rounds. */
AddRoundKey(Nr, state, RoundKey);
/* There will be Nr rounds. The first Nr-1 rounds are identical.
These Nr rounds are executed in the loop below. Last one without
InvMixColumn() */
InvShiftRows(state);
InvSubBytes(state);
AddRoundKey(Nr - 1, state, RoundKey);
InvMixColumns(state);
InvShiftRows(state);
InvSubBytes(state);
AddRoundKey(Nr - 2, state, RoundKey);
InvMixColumns(state);
InvShiftRows(state);
InvSubBytes(state);
AddRoundKey(Nr - 3, state, RoundKey);
InvMixColumns(state);
InvShiftRows(state);
InvSubBytes(state);
AddRoundKey(Nr - 4, state, RoundKey);
InvMixColumns(state);
InvShiftRows(state);
InvSubBytes(state);
AddRoundKey(Nr - 5, state, RoundKey);
InvMixColumns(state);
InvShiftRows(state);
InvSubBytes(state);
AddRoundKey(Nr - 6, state, RoundKey);
InvMixColumns(state);
InvShiftRows(state);
InvSubBytes(state);
AddRoundKey(Nr - 7, state, RoundKey);
InvMixColumns(state);
InvShiftRows(state);
InvSubBytes(state);
AddRoundKey(Nr - 8, state, RoundKey);
InvMixColumns(state);
InvShiftRows(state);
InvSubBytes(state);
AddRoundKey(Nr - 9, state, RoundKey);
InvMixColumns(state);
InvShiftRows(state);
InvSubBytes(state);
AddRoundKey(Nr - 10, state, RoundKey);
}
static void AES_ECB_decrypt(const struct AES_ctx *ctx, __u8 *buf) {
/* The next function call decrypts the PlainText with the Key using
AES algorithm. */
InvCipher((state_t *)buf, ctx->RoundKey);
}
/* rol32: From linux kernel source code */
/**
* rol32 - rotate a 32-bit value left
* @word: value to rotate
* @shift: bits to roll
*/
static inline __u32 rol32(__u32 word, unsigned int shift) {
return (word << shift) | (word >> ((-shift) & 31));
}
/* jhash.h: Jenkins hash support.
*
* Copyright (C) 2006. Bob Jenkins (bob_jenkins@burtleburtle.net)
*
* https://burtleburtle.net/bob/hash/
*
* These are the credits from Bob's sources:
*
* lookup3.c, by Bob Jenkins, May 2006, Public Domain.
*
* These are functions for producing 32-bit hashes for hash table lookup.
* hashword(), hashlittle(), hashlittle2(), hashbig(), mix(), and final()
* are externally useful functions. Routines to test the hash are included
* if SELF_TEST is defined. You can use this free for any purpose. It's in
* the public domain. It has no warranty.
*
* Copyright (C) 2009-2010 Jozsef Kadlecsik (kadlec@blackhole.kfki.hu)
*
* I've modified Bob's hash to be useful in the Linux kernel, and
* any bugs present are my fault.
* Jozsef
*/
/* __jhash_final - final mixing of 3 32-bit values (a,b,c) into c */
#define __jhash_final(a, b, c) \
{ \
c ^= b; \
c -= rol32(b, 14); \
a ^= c; \
a -= rol32(c, 11); \
b ^= a; \
b -= rol32(a, 25); \
c ^= b; \
c -= rol32(b, 16); \
a ^= c; \
a -= rol32(c, 4); \
b ^= a; \
b -= rol32(a, 14); \
c ^= b; \
c -= rol32(b, 24); \
}
/* __jhash_nwords - hash exactly 3, 2 or 1 word(s) */
static inline __u32 __jhash_nwords(__u32 a, __u32 b, __u32 c, __u32 initval) {
a += initval;
b += initval;
c += initval;
__jhash_final(a, b, c);
return c;
}
/* An arbitrary initial parameter */
#define JHASH_INITVAL 0xdeadbeef
static inline __u32 jhash_2words(__u32 a, __u32 b, __u32 initval) {
return __jhash_nwords(a, b, 0, initval + JHASH_INITVAL + (2 << 2));
}
struct {
__uint(type, BPF_MAP_TYPE_HASH);
__uint(max_entries, 255);
__type(key, __u64);
__type(value, __u32);
} cid_prefix_map SEC(".maps");
struct {
__uint(type, BPF_MAP_TYPE_REUSEPORT_SOCKARRAY);
__uint(max_entries, 255);
__type(key, __u32);
__type(value, __u32);
} reuseport_array SEC(".maps");
struct {
__uint(type, BPF_MAP_TYPE_ARRAY);
__uint(max_entries, 3);
__type(key, __u32);
__type(value, __u64);
} sk_info SEC(".maps");
typedef struct quic_hd {
__u8 *dcid;
__u32 dcidlen;
__u32 dcid_offset;
__u8 type;
} quic_hd;
#define SV_DCIDLEN 20
#define MAX_DCIDLEN 20
#define MIN_DCIDLEN 8
#define CID_PREFIXLEN 8
#define CID_PREFIX_OFFSET 1
enum {
NGTCP2_PKT_INITIAL = 0x0,
NGTCP2_PKT_0RTT = 0x1,
NGTCP2_PKT_HANDSHAKE = 0x2,
NGTCP2_PKT_SHORT = 0x40,
};
static inline int parse_quic(quic_hd *qhd, __u8 *data, __u8 *data_end) {
__u8 *p;
__u64 dcidlen;
if (*data & 0x80) {
p = data + 1 + 4;
/* Do not check the actual DCID length because we might not buffer
entire DCID here. */
dcidlen = *p;
if (dcidlen > MAX_DCIDLEN || dcidlen < MIN_DCIDLEN) {
return -1;
}
++p;
qhd->type = (*data & 0x30) >> 4;
qhd->dcid = p;
qhd->dcidlen = dcidlen;
qhd->dcid_offset = 6;
} else {
qhd->type = NGTCP2_PKT_SHORT;
qhd->dcid = data + 1;
qhd->dcidlen = SV_DCIDLEN;
qhd->dcid_offset = 1;
}
return 0;
}
static __u32 hash(const __u8 *data, __u32 datalen, __u32 initval) {
__u32 a, b;
a = (data[0] << 24) | (data[1] << 16) | (data[2] << 8) | data[3];
b = (data[4] << 24) | (data[5] << 16) | (data[6] << 8) | data[7];
return jhash_2words(a, b, initval);
}
static __u32 sk_index_from_dcid(const quic_hd *qhd,
const struct sk_reuseport_md *reuse_md,
__u64 num_socks) {
__u32 len = qhd->dcidlen;
__u32 h = reuse_md->hash;
__u8 hbuf[8];
if (len > 16) {
__builtin_memset(hbuf, 0, sizeof(hbuf));
switch (len) {
case 20:
__builtin_memcpy(hbuf, qhd->dcid + 16, 4);
break;
case 19:
__builtin_memcpy(hbuf, qhd->dcid + 16, 3);
break;
case 18:
__builtin_memcpy(hbuf, qhd->dcid + 16, 2);
break;
case 17:
__builtin_memcpy(hbuf, qhd->dcid + 16, 1);
break;
}
h = hash(hbuf, sizeof(hbuf), h);
len = 16;
}
if (len > 8) {
__builtin_memset(hbuf, 0, sizeof(hbuf));
switch (len) {
case 16:
__builtin_memcpy(hbuf, qhd->dcid + 8, 8);
break;
case 15:
__builtin_memcpy(hbuf, qhd->dcid + 8, 7);
break;
case 14:
__builtin_memcpy(hbuf, qhd->dcid + 8, 6);
break;
case 13:
__builtin_memcpy(hbuf, qhd->dcid + 8, 5);
break;
case 12:
__builtin_memcpy(hbuf, qhd->dcid + 8, 4);
break;
case 11:
__builtin_memcpy(hbuf, qhd->dcid + 8, 3);
break;
case 10:
__builtin_memcpy(hbuf, qhd->dcid + 8, 2);
break;
case 9:
__builtin_memcpy(hbuf, qhd->dcid + 8, 1);
break;
}
h = hash(hbuf, sizeof(hbuf), h);
len = 8;
}
return hash(qhd->dcid, len, h) % num_socks;
}
SEC("sk_reuseport")
int select_reuseport(struct sk_reuseport_md *reuse_md) {
__u32 sk_index, *psk_index;
__u64 *pnum_socks, *pkey;
__u32 zero = 0, key_high_idx = 1, key_low_idx = 2;
int rv;
quic_hd qhd;
__u8 qpktbuf[6 + MAX_DCIDLEN];
struct AES_ctx aes_ctx;
__u8 key[AES_KEYLEN];
__u8 *cid_prefix;
if (bpf_skb_load_bytes(reuse_md, sizeof(struct udphdr), qpktbuf,
sizeof(qpktbuf)) != 0) {
return SK_DROP;
}
pnum_socks = bpf_map_lookup_elem(&sk_info, &zero);
if (pnum_socks == NULL) {
return SK_DROP;
}
pkey = bpf_map_lookup_elem(&sk_info, &key_high_idx);
if (pkey == NULL) {
return SK_DROP;
}
__builtin_memcpy(key, pkey, sizeof(*pkey));
pkey = bpf_map_lookup_elem(&sk_info, &key_low_idx);
if (pkey == NULL) {
return SK_DROP;
}
__builtin_memcpy(key + sizeof(*pkey), pkey, sizeof(*pkey));
rv = parse_quic(&qhd, qpktbuf, qpktbuf + sizeof(qpktbuf));
if (rv != 0) {
return SK_DROP;
}
AES_init_ctx(&aes_ctx, key);
switch (qhd.type) {
case NGTCP2_PKT_INITIAL:
case NGTCP2_PKT_0RTT:
if (qhd.dcidlen == SV_DCIDLEN) {
cid_prefix = qhd.dcid + CID_PREFIX_OFFSET;
AES_ECB_decrypt(&aes_ctx, cid_prefix);
psk_index = bpf_map_lookup_elem(&cid_prefix_map, cid_prefix);
if (psk_index != NULL) {
sk_index = *psk_index;
break;
}
}
sk_index = sk_index_from_dcid(&qhd, reuse_md, *pnum_socks);
break;
case NGTCP2_PKT_HANDSHAKE:
case NGTCP2_PKT_SHORT:
if (qhd.dcidlen != SV_DCIDLEN) {
return SK_DROP;
}
cid_prefix = qhd.dcid + CID_PREFIX_OFFSET;
AES_ECB_decrypt(&aes_ctx, cid_prefix);
psk_index = bpf_map_lookup_elem(&cid_prefix_map, cid_prefix);
if (psk_index == NULL) {
sk_index = sk_index_from_dcid(&qhd, reuse_md, *pnum_socks);
break;
}
sk_index = *psk_index;
break;
default:
return SK_DROP;
}
rv = bpf_sk_select_reuseport(reuse_md, &reuseport_array, &sk_index, 0);
if (rv != 0) {
return SK_DROP;
}
return SK_PASS;
}
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