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Diffstat (limited to 'accel-pppd/ctrl/l2tp')
-rw-r--r--accel-pppd/ctrl/l2tp/l2tp_prot.h31
-rw-r--r--accel-pppd/ctrl/l2tp/packet.c203
2 files changed, 126 insertions, 108 deletions
diff --git a/accel-pppd/ctrl/l2tp/l2tp_prot.h b/accel-pppd/ctrl/l2tp/l2tp_prot.h
index 559b29cf..75cc87fa 100644
--- a/accel-pppd/ctrl/l2tp/l2tp_prot.h
+++ b/accel-pppd/ctrl/l2tp/l2tp_prot.h
@@ -5,17 +5,16 @@
#define L2TP_PORT 1701
+#define L2TP_FLAG_T 0x8000
+#define L2TP_FLAG_L 0x4000
+#define L2TP_FLAG_S 0x0800
+#define L2TP_FLAG_O 0x0200
+#define L2TP_FLAG_P 0x0100
+#define L2TP_VER_MASK 0x000f
+
struct l2tp_hdr_t
{
- uint8_t P:1;
- uint8_t O:1;
- uint8_t reserved2:1;
- uint8_t S:1;
- uint8_t reserved1:2;
- uint8_t L:1;
- uint8_t T:1;
- uint8_t ver:4;
- uint8_t reserved3:4;
+ uint16_t flags;
uint16_t length;
union {
struct {
@@ -28,18 +27,13 @@ struct l2tp_hdr_t
uint16_t Nr;
} __attribute__((packed));
-/*#define L2TP_T(hdr) (hdr->flags >> 15)
-#define L2TP_L(hdr) ((hdr->flags >> 14) & 1)
-#define L2TP_S(hdr) ((hdr->flags >> 10) & 1)
-#define L2TP_O(hdr) ((hdr->flags >> 8) & 1)
-#define L2TP_VER(hdr) (hdr->flags & 0xf)*/
+#define L2TP_AVP_FLAG_M 0x8000
+#define L2TP_AVP_FLAG_H 0x4000
+#define L2TP_AVP_LEN_MASK 0x03ff
struct l2tp_avp_t
{
- uint16_t length:10;
- uint16_t reserved:4;
- uint16_t H:1;
- uint16_t M:1;
+ uint16_t flags;
uint16_t vendor;
uint16_t type;
uint8_t val[0];
@@ -53,4 +47,3 @@ struct l2tp_avp_result_code
} __attribute__((packed));
#endif
-
diff --git a/accel-pppd/ctrl/l2tp/packet.c b/accel-pppd/ctrl/l2tp/packet.c
index 455c486e..97e205f3 100644
--- a/accel-pppd/ctrl/l2tp/packet.c
+++ b/accel-pppd/ctrl/l2tp/packet.c
@@ -28,12 +28,18 @@ void l2tp_packet_print(const struct l2tp_packet_t *pack,
const struct l2tp_attr_t *attr;
const struct l2tp_dict_value_t *val;
- if (pack->hdr.ver == 2) {
+ switch (pack->hdr.flags & L2TP_VER_MASK) {
+ case 2:
print("[L2TP tid=%u sid=%u", ntohs(pack->hdr.tid), ntohs(pack->hdr.sid));
log_ppp_debug(" Ns=%u Nr=%u", ntohs(pack->hdr.Ns), ntohs(pack->hdr.Nr));
- } else {
+ break;
+ case 3:
print("[L2TP cid=%u", pack->hdr.cid);
log_ppp_debug(" Ns=%u Nr=%u", ntohs(pack->hdr.Ns), ntohs(pack->hdr.Nr));
+ break;
+ default:
+ print("[L2TP unknown version]\n");
+ return;
}
list_for_each_entry(attr, &pack->attrs, entry) {
@@ -72,10 +78,7 @@ struct l2tp_packet_t *l2tp_packet_alloc(int ver, int msg_type,
memset(pack, 0, sizeof(*pack));
INIT_LIST_HEAD(&pack->attrs);
- pack->hdr.ver = ver;
- pack->hdr.T = 1;
- pack->hdr.L = 1;
- pack->hdr.S = 1;
+ pack->hdr.flags = L2TP_FLAG_T | L2TP_FLAG_L | L2TP_FLAG_S | (ver & L2TP_VER_MASK);
memcpy(&pack->addr, addr, sizeof(*addr));
pack->hide_avps = H;
pack->secret = secret;
@@ -150,21 +153,23 @@ static int decode_avp(struct l2tp_avp_t *avp, const struct l2tp_attr_t *RV,
uint8_t md5[MD5_DIGEST_LENGTH];
uint8_t p1[MD5_DIGEST_LENGTH];
uint8_t *prev_block = NULL;
+ uint16_t avp_len;
uint16_t attr_len;
uint16_t orig_attr_len;
uint16_t bytes_left;
uint16_t blocks_left;
uint16_t last_block_len;
- if (avp->length < sizeof(struct l2tp_avp_t) + 2) {
+ avp_len = avp->flags & L2TP_AVP_LEN_MASK;
+ if (avp_len < sizeof(struct l2tp_avp_t) + 2) {
/* Hidden AVPs must contain at least two bytes
for storing original attribute length */
log_warn("l2tp: incorrect hidden avp received (type %hu):"
" length too small (%hu bytes)\n",
- ntohs(avp->type), avp->length);
+ ntohs(avp->type), avp_len);
return -1;
}
- attr_len = avp->length - sizeof(struct l2tp_avp_t);
+ attr_len = avp_len - sizeof(struct l2tp_avp_t);
/* Decode first block */
MD5_Init(&md5_ctx);
@@ -228,31 +233,29 @@ static int decode_avp(struct l2tp_avp_t *avp, const struct l2tp_attr_t *RV,
int l2tp_recv(int fd, struct l2tp_packet_t **p, struct in_pktinfo *pkt_info,
const char *secret, size_t secret_len)
{
- int n, length;
- uint8_t *buf;
+ struct l2tp_packet_t *pack;
struct l2tp_hdr_t *hdr;
struct l2tp_avp_t *avp;
- struct l2tp_dict_attr_t *da;
- struct l2tp_attr_t *attr, *RV = NULL;
- uint8_t *ptr;
- struct l2tp_packet_t *pack;
+ struct l2tp_attr_t *RV = NULL;
struct sockaddr_in addr;
- socklen_t len = sizeof(addr);
- struct msghdr msg;
- char msg_control[128];
- struct cmsghdr *cmsg;
+ socklen_t addr_len;
uint16_t orig_avp_len;
void *orig_avp_val;
+ uint8_t *buf, *ptr;
+ int n, length;
- *p = NULL;
+ *p = NULL;
if (pkt_info) {
+ struct msghdr msg;
+ struct cmsghdr *cmsg;
+ char msg_control[128];
+
memset(&msg, 0, sizeof(msg));
msg.msg_control = msg_control;
- msg.msg_controllen = 128;
+ msg.msg_controllen = sizeof(msg_control);
n = recvmsg(fd, &msg, MSG_PEEK);
-
if (n < 0) {
if (errno == EAGAIN)
return -1;
@@ -276,8 +279,8 @@ int l2tp_recv(int fd, struct l2tp_packet_t **p, struct in_pktinfo *pkt_info,
hdr = (struct l2tp_hdr_t *)buf;
ptr = (uint8_t *)(hdr + 1);
- n = recvfrom(fd, buf, L2TP_MAX_PACKET_SIZE, 0, &addr, &len);
-
+ addr_len = sizeof(addr);
+ n = recvfrom(fd, buf, L2TP_MAX_PACKET_SIZE, 0, &addr, &addr_len);
if (n < 0) {
mempool_free(buf);
if (errno == EAGAIN) {
@@ -289,45 +292,50 @@ int l2tp_recv(int fd, struct l2tp_packet_t **p, struct in_pktinfo *pkt_info,
return 0;
}
- if (n < 6) {
+ if (n < sizeof(*hdr)) {
if (conf_verbose)
log_warn("l2tp: short packet received (%i/%zu)\n", n, sizeof(*hdr));
goto out_err_hdr;
}
- if (hdr->T == 0)
+ hdr->flags = ntohs(hdr->flags);
+ if (!(hdr->flags & L2TP_FLAG_T))
goto out_err_hdr;
-
- if (n < ntohs(hdr->length)) {
+ if (!(hdr->flags & L2TP_FLAG_L)) {
if (conf_verbose)
- log_warn("l2tp: short packet received (%i/%i)\n", n, ntohs(hdr->length));
+ log_warn("l2tp: incorrect control message received (L=0)\n");
goto out_err_hdr;
}
-
- if (hdr->ver == 2) {
- if (hdr->L == 0) {
- if (conf_verbose)
- log_warn("l2tp: incorrect message received (L=0)\n");
- if (!conf_avp_permissive)
- goto out_err_hdr;
- }
-
- if (hdr->S == 0) {
+ if (!(hdr->flags & L2TP_FLAG_S)) {
+ if (conf_verbose)
+ log_warn("l2tp: incorrect control message received (S=0)\n");
+ goto out_err_hdr;
+ }
+ switch (hdr->flags & L2TP_VER_MASK) {
+ case 2:
+ if (hdr->flags & L2TP_FLAG_O) {
if (conf_verbose)
- log_warn("l2tp: incorrect message received (S=0)\n");
- if (!conf_avp_permissive)
- goto out_err_hdr;
+ log_warn("l2tp: incorrect control message received (O=1)\n");
+ goto out_err_hdr;
}
+ break;
+ case 3:
+ break;
+ default:
+ if (conf_verbose)
+ log_warn("l2tp: protocol version %i is not supported\n",
+ hdr->flags & L2TP_VER_MASK);
+ goto out_err_hdr;
+ }
- if (hdr->O == 1) {
- if (conf_verbose)
- log_warn("l2tp: incorrect message received (O=1)\n");
- if (!conf_avp_permissive)
- goto out_err_hdr;
- }
- } else if (hdr->ver != 3) {
+ length = ntohs(hdr->length);
+ if (length < sizeof(*hdr)) {
if (conf_verbose)
- log_warn("l2tp: protocol version %i is not supported\n", hdr->ver);
+ log_warn("l2tp: short packet received (%i/%zu)\n", length, sizeof(*hdr));
+ goto out_err_hdr;
+ } else if (n < length) {
+ if (conf_verbose)
+ log_warn("l2tp: short packet received (%i/%i)\n", n, length);
goto out_err_hdr;
}
@@ -342,13 +350,27 @@ int l2tp_recv(int fd, struct l2tp_packet_t **p, struct in_pktinfo *pkt_info,
memcpy(&pack->addr, &addr, sizeof(addr));
memcpy(&pack->hdr, hdr, sizeof(*hdr));
- length = ntohs(hdr->length) - sizeof(*hdr);
+ length -= sizeof(*hdr);
- while (length) {
- *(uint16_t *)ptr = ntohs(*(uint16_t *)ptr);
- avp = (struct l2tp_avp_t *)ptr;
+ while (length > 0) {
+ struct l2tp_dict_attr_t *da;
+ struct l2tp_attr_t *attr;
+ uint16_t avp_len;
- if (avp->length > length) {
+ if (length < sizeof(*avp)) {
+ if (conf_verbose)
+ log_warn("l2tp: short avp received\n");
+ goto out_err;
+ }
+
+ avp = (struct l2tp_avp_t *)ptr;
+ avp->flags = ntohs(avp->flags);
+ avp_len = avp->flags & L2TP_AVP_LEN_MASK;
+ if (avp_len < sizeof(*avp)) {
+ if (conf_verbose)
+ log_warn("l2tp: short avp received\n");
+ goto out_err;
+ } else if (length < avp_len) {
if (conf_verbose)
log_warn("l2tp: incorrect avp received (exceeds message length)\n");
goto out_err;
@@ -359,26 +381,32 @@ int l2tp_recv(int fd, struct l2tp_packet_t **p, struct in_pktinfo *pkt_info,
da = l2tp_dict_find_attr_by_id(ntohs(avp->type));
if (!da) {
- if (conf_verbose)
- log_warn("l2tp: unknown avp received (type=%i, M=%u)\n", ntohs(avp->type), avp->M);
- if (avp->M && !conf_avp_permissive)
+ if (conf_verbose) {
+ log_warn("l2tp: unknown avp received (type=%i, M=%u)\n",
+ ntohs(avp->type), !!(avp->flags & L2TP_AVP_FLAG_M));
+ }
+ if ((avp->flags & L2TP_AVP_FLAG_M) && !conf_avp_permissive)
goto out_err;
} else {
- if (da->M != -1 && da->M != avp->M) {
- if (conf_verbose)
- log_warn("l2tp: incorrect avp received (type=%i, M=%i, must be %i)\n", ntohs(avp->type), avp->M, da->M);
+ if (da->M != -1 && !da->M != !(avp->flags & L2TP_AVP_FLAG_M)) {
+ if (conf_verbose) {
+ log_warn("l2tp: incorrect avp received (type=%i, M=%i, must be %i)\n",
+ ntohs(avp->type), !!(avp->flags & L2TP_AVP_FLAG_M), da->M);
+ }
if (!conf_avp_permissive)
goto out_err;
}
- if (da->H != -1 && da->H != avp->H) {
- if (conf_verbose)
- log_warn("l2tp: incorrect avp received (type=%i, H=%i, must be %i)\n", ntohs(avp->type), avp->H, da->H);
+ if (da->H != -1 && !da->H != !(avp->flags & L2TP_AVP_FLAG_H)) {
+ if (conf_verbose) {
+ log_warn("l2tp: incorrect avp received (type=%i, H=%i, must be %i)\n",
+ ntohs(avp->type), !!(avp->flags & L2TP_AVP_FLAG_H), da->H);
+ }
if (!conf_avp_permissive)
goto out_err;
}
- if (avp->H) {
+ if (avp->flags & L2TP_AVP_FLAG_H) {
if (!RV) {
if (conf_verbose)
log_warn("l2tp: incorrect avp received (type=%i, H=1, but Random-Vector is not received)\n", ntohs(avp->type));
@@ -393,24 +421,21 @@ int l2tp_recv(int fd, struct l2tp_packet_t **p, struct in_pktinfo *pkt_info,
}
if (decode_avp(avp, RV, secret, secret_len) < 0)
goto out_err;
- }
- attr = mempool_alloc(attr_pool);
- memset(attr, 0, sizeof(*attr));
- list_add_tail(&attr->entry, &pack->attrs);
-
- if (avp->H) {
orig_avp_len = ntohs(*(uint16_t *)avp->val) + sizeof(*avp);
orig_avp_val = avp->val + sizeof(uint16_t);
} else {
- orig_avp_len = avp->length;
+ orig_avp_len = avp_len;
orig_avp_val = avp->val;
}
+ attr = mempool_alloc(attr_pool);
+ memset(attr, 0, sizeof(*attr));
attr->attr = da;
- attr->M = avp->M;
+ attr->M = !!(avp->flags & L2TP_AVP_FLAG_M);
attr->H = 0;
attr->length = orig_avp_len - sizeof(*avp);
+ list_add_tail(&attr->entry, &pack->attrs);
if (attr->attr->id == Random_Vector)
RV = attr;
@@ -447,8 +472,8 @@ int l2tp_recv(int fd, struct l2tp_packet_t **p, struct in_pktinfo *pkt_info,
}
}
skip:
- ptr += avp->length;
- length -= avp->length;
+ ptr += avp_len;
+ length -= avp_len;
}
*p = pack;
@@ -473,21 +498,22 @@ out_err_mem:
int l2tp_packet_send(int sock, struct l2tp_packet_t *pack)
{
- uint8_t *buf = mempool_alloc(buf_pool);
+ struct l2tp_hdr_t *hdr;
struct l2tp_avp_t *avp;
struct l2tp_attr_t *attr;
- uint8_t *ptr;
- int n;
- int len = sizeof(pack->hdr);
+ uint8_t *buf, *ptr;
+ int n, len;
+ buf = mempool_alloc(buf_pool);
if (!buf) {
log_emerg("l2tp: out of memory\n");
return -1;
}
memset(buf, 0, L2TP_MAX_PACKET_SIZE);
-
- ptr = buf + sizeof(pack->hdr);
+ hdr = (struct l2tp_hdr_t *)buf;
+ ptr = (uint8_t *)(hdr + 1);
+ len = sizeof(pack->hdr);
list_for_each_entry(attr, &pack->attrs, entry) {
if (len + sizeof(*avp) + attr->length >= L2TP_MAX_PACKET_SIZE) {
@@ -497,10 +523,9 @@ int l2tp_packet_send(int sock, struct l2tp_packet_t *pack)
}
avp = (struct l2tp_avp_t *)ptr;
avp->type = htons(attr->attr->id);
- avp->M = attr->M;
- avp->H = attr->H;
- avp->length = sizeof(*avp) + attr->length;
- *(uint16_t *)ptr = htons(*(uint16_t *)ptr);
+ avp->flags = htons((attr->M ? L2TP_AVP_FLAG_M : 0) |
+ (attr->H ? L2TP_AVP_FLAG_H : 0) |
+ ((sizeof(*avp) + attr->length) & L2TP_AVP_LEN_MASK));
if (attr->H)
memcpy(avp->val, attr->val.octets, attr->length);
else
@@ -525,9 +550,9 @@ int l2tp_packet_send(int sock, struct l2tp_packet_t *pack)
pack->hdr.length = htons(len);
memcpy(buf, &pack->hdr, sizeof(pack->hdr));
+ hdr->flags = htons(pack->hdr.flags);
- n = sendto(sock, buf, ntohs(pack->hdr.length), 0,
- &pack->addr, sizeof(pack->addr));
+ n = sendto(sock, buf, len, 0, &pack->addr, sizeof(pack->addr));
mempool_free(buf);
if (n < 0) {
@@ -541,9 +566,9 @@ int l2tp_packet_send(int sock, struct l2tp_packet_t *pack)
}
}
- if (n != ntohs(pack->hdr.length)) {
+ if (n != len) {
if (conf_verbose)
- log_warn("l2tp: short write (%i/%i)\n", n, ntohs(pack->hdr.length));
+ log_warn("l2tp: short write (%i/%i)\n", n, len);
}
return 0;
generated by cgit v1.2.3 (git 2.39.1) at 2025-01-31 03:55:41 +0000