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mptcp: Add ADD_ADDR handling
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Add handling for sending and receiving the ADD_ADDR, ADD_ADDR6,
and RM_ADDR suboptions.

Co-developed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Co-developed-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Peter Krystad <peter.krystad@linux.intel.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Peter Krystad authored and David S. Miller committed Mar 30, 2020
1 parent 41b1450 commit 3df523a
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Showing 5 changed files with 262 additions and 18 deletions.
20 changes: 18 additions & 2 deletions include/linux/tcp.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -86,16 +86,30 @@ struct mptcp_options_received {
u64 data_seq;
u32 subflow_seq;
u16 data_len;
u8 mp_capable : 1,
u16 mp_capable : 1,
mp_join : 1,
dss : 1;
dss : 1,
add_addr : 1,
rm_addr : 1,
family : 4,
echo : 1;
u8 use_map:1,
dsn64:1,
data_fin:1,
use_ack:1,
ack64:1,
mpc_map:1,
__unused:2;
u8 addr_id;
u8 rm_id;
union {
struct in_addr addr;
#if IS_ENABLED(CONFIG_MPTCP_IPV6)
struct in6_addr addr6;
#endif
};
u64 ahmac;
u16 port;
};
#endif

Expand Down Expand Up @@ -131,6 +145,8 @@ static inline void tcp_clear_options(struct tcp_options_received *rx_opt)
#if IS_ENABLED(CONFIG_MPTCP)
rx_opt->mptcp.mp_capable = 0;
rx_opt->mptcp.mp_join = 0;
rx_opt->mptcp.add_addr = 0;
rx_opt->mptcp.rm_addr = 0;
rx_opt->mptcp.dss = 0;
#endif
}
Expand Down
9 changes: 9 additions & 0 deletions include/net/mptcp.h
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Original file line number Diff line number Diff line change
Expand Up @@ -33,6 +33,15 @@ struct mptcp_out_options {
u16 suboptions;
u64 sndr_key;
u64 rcvr_key;
union {
struct in_addr addr;
#if IS_ENABLED(CONFIG_MPTCP_IPV6)
struct in6_addr addr6;
#endif
};
u8 addr_id;
u64 ahmac;
u8 rm_id;
struct mptcp_ext ext_copy;
#endif
};
Expand Down
17 changes: 11 additions & 6 deletions net/mptcp/crypto.c
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Original file line number Diff line number Diff line change
Expand Up @@ -44,8 +44,7 @@ void mptcp_crypto_key_sha(u64 key, u32 *token, u64 *idsn)
*idsn = be64_to_cpu(*((__be64 *)&mptcp_hashed_key[6]));
}

void mptcp_crypto_hmac_sha(u64 key1, u64 key2, u32 nonce1, u32 nonce2,
void *hmac)
void mptcp_crypto_hmac_sha(u64 key1, u64 key2, u8 *msg, int len, void *hmac)
{
u8 input[SHA256_BLOCK_SIZE + SHA256_DIGEST_SIZE];
__be32 mptcp_hashed_key[SHA256_DIGEST_WORDS];
Expand All @@ -55,6 +54,9 @@ void mptcp_crypto_hmac_sha(u64 key1, u64 key2, u32 nonce1, u32 nonce2,
u8 key2be[8];
int i;

if (WARN_ON_ONCE(len > SHA256_DIGEST_SIZE))
len = SHA256_DIGEST_SIZE;

put_unaligned_be64(key1, key1be);
put_unaligned_be64(key2, key2be);

Expand All @@ -65,11 +67,10 @@ void mptcp_crypto_hmac_sha(u64 key1, u64 key2, u32 nonce1, u32 nonce2,
for (i = 0; i < 8; i++)
input[i + 8] ^= key2be[i];

put_unaligned_be32(nonce1, &input[SHA256_BLOCK_SIZE]);
put_unaligned_be32(nonce2, &input[SHA256_BLOCK_SIZE + 4]);
memcpy(&input[SHA256_BLOCK_SIZE], msg, len);

sha256_init(&state);
sha256_update(&state, input, SHA256_BLOCK_SIZE + 8);
sha256_update(&state, input, SHA256_BLOCK_SIZE + len);

/* emit sha256(K1 || msg) on the second input block, so we can
* reuse 'input' for the last hashing
Expand Down Expand Up @@ -125,6 +126,7 @@ static int __init test_mptcp_crypto(void)
char hmac[20], hmac_hex[41];
u32 nonce1, nonce2;
u64 key1, key2;
u8 msg[8];
int i, j;

for (i = 0; i < ARRAY_SIZE(tests); ++i) {
Expand All @@ -134,7 +136,10 @@ static int __init test_mptcp_crypto(void)
nonce1 = be32_to_cpu(*((__be32 *)&tests[i].msg[0]));
nonce2 = be32_to_cpu(*((__be32 *)&tests[i].msg[4]));

mptcp_crypto_hmac_sha(key1, key2, nonce1, nonce2, hmac);
put_unaligned_be32(nonce1, &msg[0]);
put_unaligned_be32(nonce2, &msg[4]);

mptcp_crypto_hmac_sha(key1, key2, msg, 8, hmac);
for (j = 0; j < 20; ++j)
sprintf(&hmac_hex[j << 1], "%02x", hmac[j] & 0xff);
hmac_hex[40] = 0;
Expand Down
206 changes: 198 additions & 8 deletions net/mptcp/options.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -178,6 +178,71 @@ void mptcp_parse_option(const struct sk_buff *skb, const unsigned char *ptr,

break;

case MPTCPOPT_ADD_ADDR:
mp_opt->echo = (*ptr++) & MPTCP_ADDR_ECHO;
if (!mp_opt->echo) {
if (opsize == TCPOLEN_MPTCP_ADD_ADDR ||
opsize == TCPOLEN_MPTCP_ADD_ADDR_PORT)
mp_opt->family = MPTCP_ADDR_IPVERSION_4;
#if IS_ENABLED(CONFIG_MPTCP_IPV6)
else if (opsize == TCPOLEN_MPTCP_ADD_ADDR6 ||
opsize == TCPOLEN_MPTCP_ADD_ADDR6_PORT)
mp_opt->family = MPTCP_ADDR_IPVERSION_6;
#endif
else
break;
} else {
if (opsize == TCPOLEN_MPTCP_ADD_ADDR_BASE ||
opsize == TCPOLEN_MPTCP_ADD_ADDR_BASE_PORT)
mp_opt->family = MPTCP_ADDR_IPVERSION_4;
#if IS_ENABLED(CONFIG_MPTCP_IPV6)
else if (opsize == TCPOLEN_MPTCP_ADD_ADDR6_BASE ||
opsize == TCPOLEN_MPTCP_ADD_ADDR6_BASE_PORT)
mp_opt->family = MPTCP_ADDR_IPVERSION_6;
#endif
else
break;
}

mp_opt->add_addr = 1;
mp_opt->port = 0;
mp_opt->addr_id = *ptr++;
pr_debug("ADD_ADDR: id=%d", mp_opt->addr_id);
if (mp_opt->family == MPTCP_ADDR_IPVERSION_4) {
memcpy((u8 *)&mp_opt->addr.s_addr, (u8 *)ptr, 4);
ptr += 4;
if (opsize == TCPOLEN_MPTCP_ADD_ADDR_PORT ||
opsize == TCPOLEN_MPTCP_ADD_ADDR_BASE_PORT) {
mp_opt->port = get_unaligned_be16(ptr);
ptr += 2;
}
}
#if IS_ENABLED(CONFIG_MPTCP_IPV6)
else {
memcpy(mp_opt->addr6.s6_addr, (u8 *)ptr, 16);
ptr += 16;
if (opsize == TCPOLEN_MPTCP_ADD_ADDR6_PORT ||
opsize == TCPOLEN_MPTCP_ADD_ADDR6_BASE_PORT) {
mp_opt->port = get_unaligned_be16(ptr);
ptr += 2;
}
}
#endif
if (!mp_opt->echo) {
mp_opt->ahmac = get_unaligned_be64(ptr);
ptr += 8;
}
break;

case MPTCPOPT_RM_ADDR:
if (opsize != TCPOLEN_MPTCP_RM_ADDR_BASE)
break;

mp_opt->rm_addr = 1;
mp_opt->rm_id = *ptr++;
pr_debug("RM_ADDR: id=%d", mp_opt->rm_id);
break;

default:
break;
}
Expand Down Expand Up @@ -386,13 +451,93 @@ static bool mptcp_established_options_dss(struct sock *sk, struct sk_buff *skb,
return true;
}

static u64 add_addr_generate_hmac(u64 key1, u64 key2, u8 addr_id,
struct in_addr *addr)
{
u8 hmac[MPTCP_ADDR_HMAC_LEN];
u8 msg[7];

msg[0] = addr_id;
memcpy(&msg[1], &addr->s_addr, 4);
msg[5] = 0;
msg[6] = 0;

mptcp_crypto_hmac_sha(key1, key2, msg, 7, hmac);

return get_unaligned_be64(hmac);
}

#if IS_ENABLED(CONFIG_MPTCP_IPV6)
static u64 add_addr6_generate_hmac(u64 key1, u64 key2, u8 addr_id,
struct in6_addr *addr)
{
u8 hmac[MPTCP_ADDR_HMAC_LEN];
u8 msg[19];

msg[0] = addr_id;
memcpy(&msg[1], &addr->s6_addr, 16);
msg[17] = 0;
msg[18] = 0;

mptcp_crypto_hmac_sha(key1, key2, msg, 19, hmac);

return get_unaligned_be64(hmac);
}
#endif

static bool mptcp_established_options_addr(struct sock *sk,
unsigned int *size,
unsigned int remaining,
struct mptcp_out_options *opts)
{
struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
struct mptcp_sock *msk = mptcp_sk(subflow->conn);
struct sockaddr_storage saddr;
u8 id;

id = 0;
memset(&saddr, 0, sizeof(saddr));

if (saddr.ss_family == AF_INET) {
if (remaining < TCPOLEN_MPTCP_ADD_ADDR)
return false;
opts->suboptions |= OPTION_MPTCP_ADD_ADDR;
opts->addr_id = id;
opts->addr = ((struct sockaddr_in *)&saddr)->sin_addr;
opts->ahmac = add_addr_generate_hmac(msk->local_key,
msk->remote_key,
opts->addr_id,
&opts->addr);
*size = TCPOLEN_MPTCP_ADD_ADDR;
}
#if IS_ENABLED(CONFIG_MPTCP_IPV6)
else if (saddr.ss_family == AF_INET6) {
if (remaining < TCPOLEN_MPTCP_ADD_ADDR6)
return false;
opts->suboptions |= OPTION_MPTCP_ADD_ADDR6;
opts->addr_id = id;
opts->ahmac = add_addr6_generate_hmac(msk->local_key,
msk->remote_key,
opts->addr_id,
&opts->addr6);
opts->addr6 = ((struct sockaddr_in6 *)&saddr)->sin6_addr;
*size = TCPOLEN_MPTCP_ADD_ADDR6;
}
#endif
pr_debug("addr_id=%d, ahmac=%llu", opts->addr_id, opts->ahmac);

return true;
}

bool mptcp_established_options(struct sock *sk, struct sk_buff *skb,
unsigned int *size, unsigned int remaining,
struct mptcp_out_options *opts)
{
unsigned int opt_size = 0;
bool ret = false;

opts->suboptions = 0;

if (mptcp_established_options_mp(sk, skb, &opt_size, remaining, opts))
ret = true;
else if (mptcp_established_options_dss(sk, skb, &opt_size, remaining,
Expand All @@ -407,6 +552,11 @@ bool mptcp_established_options(struct sock *sk, struct sk_buff *skb,

*size += opt_size;
remaining -= opt_size;
if (mptcp_established_options_addr(sk, &opt_size, remaining, opts)) {
*size += opt_size;
remaining -= opt_size;
ret = true;
}

return ret;
}
Expand Down Expand Up @@ -521,10 +671,9 @@ void mptcp_write_options(__be32 *ptr, struct mptcp_out_options *opts)
else
len = TCPOLEN_MPTCP_MPC_ACK;

*ptr++ = htonl((TCPOPT_MPTCP << 24) | (len << 16) |
(MPTCPOPT_MP_CAPABLE << 12) |
(MPTCP_SUPPORTED_VERSION << 8) |
MPTCP_CAP_HMAC_SHA256);
*ptr++ = mptcp_option(MPTCPOPT_MP_CAPABLE, len,
MPTCP_SUPPORTED_VERSION,
MPTCP_CAP_HMAC_SHA256);

if (!((OPTION_MPTCP_MPC_SYNACK | OPTION_MPTCP_MPC_ACK) &
opts->suboptions))
Expand All @@ -546,6 +695,50 @@ void mptcp_write_options(__be32 *ptr, struct mptcp_out_options *opts)
}

mp_capable_done:
if (OPTION_MPTCP_ADD_ADDR & opts->suboptions) {
if (opts->ahmac)
*ptr++ = mptcp_option(MPTCPOPT_ADD_ADDR,
TCPOLEN_MPTCP_ADD_ADDR, 0,
opts->addr_id);
else
*ptr++ = mptcp_option(MPTCPOPT_ADD_ADDR,
TCPOLEN_MPTCP_ADD_ADDR_BASE,
MPTCP_ADDR_ECHO,
opts->addr_id);
memcpy((u8 *)ptr, (u8 *)&opts->addr.s_addr, 4);
ptr += 1;
if (opts->ahmac) {
put_unaligned_be64(opts->ahmac, ptr);
ptr += 2;
}
}

#if IS_ENABLED(CONFIG_MPTCP_IPV6)
if (OPTION_MPTCP_ADD_ADDR6 & opts->suboptions) {
if (opts->ahmac)
*ptr++ = mptcp_option(MPTCPOPT_ADD_ADDR,
TCPOLEN_MPTCP_ADD_ADDR6, 0,
opts->addr_id);
else
*ptr++ = mptcp_option(MPTCPOPT_ADD_ADDR,
TCPOLEN_MPTCP_ADD_ADDR6_BASE,
MPTCP_ADDR_ECHO,
opts->addr_id);
memcpy((u8 *)ptr, opts->addr6.s6_addr, 16);
ptr += 4;
if (opts->ahmac) {
put_unaligned_be64(opts->ahmac, ptr);
ptr += 2;
}
}
#endif

if (OPTION_MPTCP_RM_ADDR & opts->suboptions) {
*ptr++ = mptcp_option(MPTCPOPT_RM_ADDR,
TCPOLEN_MPTCP_RM_ADDR_BASE,
0, opts->rm_id);
}

if (opts->ext_copy.use_ack || opts->ext_copy.use_map) {
struct mptcp_ext *mpext = &opts->ext_copy;
u8 len = TCPOLEN_MPTCP_DSS_BASE;
Expand All @@ -567,10 +760,7 @@ void mptcp_write_options(__be32 *ptr, struct mptcp_out_options *opts)
flags |= MPTCP_DSS_DATA_FIN;
}

*ptr++ = htonl((TCPOPT_MPTCP << 24) |
(len << 16) |
(MPTCPOPT_DSS << 12) |
(flags));
*ptr++ = mptcp_option(MPTCPOPT_DSS, len, 0, flags);

if (mpext->use_ack) {
put_unaligned_be64(mpext->data_ack, ptr);
Expand Down
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