Try to minimise the amount of buffers allocated and copied by clients when building a message attribute that is a concatenation of other buffers, such as an IE sequence. The client would the following three calls: l_genl_msg_enter_nested l_genl_msg_attr_append_data l_genl_msg_leave_nested --- ell/genl.c | 26 ++++++++++++++++++++++++++ ell/genl.h | 1 + 2 files changed, 27 insertions(+) diff --git a/ell/genl.c b/ell/genl.c index 85e447a..aefea5f 100644 --- a/ell/genl.c +++ b/ell/genl.c @@ -828,14 +828,40 @@ LIB_EXPORT bool l_genl_msg_leave_nested(struct l_genl_msg *msg) if (unlikely(msg->nesting_level == 0)) return false; + if (NLA_ALIGN(msg->len) > msg->size) + return false; + nla = msg->nests[msg->nesting_level - 1]; nla->nla_len = msg->len - nla->nla_len; msg->nesting_level -= 1; + msg->len = NLA_ALIGN(msg->len); + return true; } +LIB_EXPORT void *l_genl_msg_attr_append_data(struct l_genl_msg *msg, + uint16_t len) +{ + void *ptr; + + if (unlikely(!msg)) + return false; + + if (msg->len + len > msg->size) + return false; + + if (unlikely(msg->nesting_level == 0)) + return false; + + ptr = msg->data + msg->len; + + msg->len += len; + + return ptr; +} + #define NLA_OK(nla,len) ((len) >= (int) sizeof(struct nlattr) && \ (nla)->nla_len >= sizeof(struct nlattr) && \ (nla)->nla_len <= (len)) diff --git a/ell/genl.h b/ell/genl.h index 5b37d55..5bfa459 100644 --- a/ell/genl.h +++ b/ell/genl.h @@ -73,6 +73,7 @@ bool l_genl_msg_append_attr(struct l_genl_msg *msg, uint16_t type, uint16_t len, const void *data); bool l_genl_msg_enter_nested(struct l_genl_msg *msg, uint16_t type); bool l_genl_msg_leave_nested(struct l_genl_msg *msg); +void *l_genl_msg_attr_append_data(struct l_genl_msg *msg, uint16_t len); bool l_genl_attr_init(struct l_genl_attr *attr, struct l_genl_msg *msg); bool l_genl_attr_next(struct l_genl_attr *attr, uint16_t *type, -- 2.7.4