diff options
Diffstat (limited to 'bpf')
| -rw-r--r-- | bpf/CMakeLists.txt | 13 | ||||
| -rw-r--r-- | bpf/Makefile.am | 40 | ||||
| -rw-r--r-- | bpf/reuseport_kern.c | 663 |
3 files changed, 716 insertions, 0 deletions
diff --git a/bpf/CMakeLists.txt b/bpf/CMakeLists.txt new file mode 100644 index 0000000..904b821 --- /dev/null +++ b/bpf/CMakeLists.txt @@ -0,0 +1,13 @@ +if(LIBBPF_FOUND) + add_custom_command(OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/reuseport_kern.o" + COMMAND ${CMAKE_C_COMPILER} ${BPFCFLAGS} ${EXTRABPFCFLAGS} -I${LIBBPF_INCLUDE_DIRS} -target bpf -c reuseport_kern.c -o "${CMAKE_CURRENT_BINARY_DIR}/reuseport_kern.o" + WORKING_DIRECTORY "${CMAKE_CURRENT_SOURCE_DIR}" + VERBATIM) + + add_custom_target(bpf ALL + DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/reuseport_kern.o" + VERBATIM) + + install(FILES "${CMAKE_CURRENT_BINARY_DIR}/reuseport_kern.o" + DESTINATION "${CMAKE_INSTALL_LIBDIR}/${CMAKE_PROJECT_NAME}") +endif() diff --git a/bpf/Makefile.am b/bpf/Makefile.am new file mode 100644 index 0000000..9017fd9 --- /dev/null +++ b/bpf/Makefile.am @@ -0,0 +1,40 @@ +# 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. + +EXTRA_DIST = CMakeLists.txt reuseport_kern.c + +if HAVE_LIBBPF + +bpf_pkglibdir = $(pkglibdir) +bpf_pkglib_DATA = reuseport_kern.o + +all: $(builddir)/reuseport_kern.o + +$(builddir)/reuseport_kern.o: reuseport_kern.c + $(CC) @LIBBPF_CFLAGS@ @BPFCFLAGS@ @EXTRABPFCFLAGS@ \ + -target bpf -c $< -o $@ + +clean-local: + -rm -f reuseport_kern.o + +endif # HAVE_LIBBPF diff --git a/bpf/reuseport_kern.c b/bpf/reuseport_kern.c new file mode 100644 index 0000000..74c08c5 --- /dev/null +++ b/bpf/reuseport_kern.c @@ -0,0 +1,663 @@ +/* + * 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; +} |