SCTP 库的简述和代码 (3)

--- 如转请保留作者信息 jundai2009@gmail.com

接这上回说, 上面, g_sctp_fsm 是状态列表入口, 不同的状态下,处理网络包的方法不一样, 就是说处理的API不一样, 那这API就在这里选择.

状态表格中, 左边fsm_handler_fn 是执行动作, 右边是下面将要进入的状态.

关于这个库的状态机设计, 还有下面两个比较重要的宏

#define SCTP_TRANSFER_STATE(assoc, new_state) do {\
    if ((assoc)->cur_state != new_state) {\
        sctp_enter_state(assoc, new_state);\
        assoc->cur_state = new_state;\
    }\
}while(0);

#define SCTP_PROC_PKG(instance, assoc, pkg, parsed_info, new_assoc) do {\
    sctp_state old_state, new_state; \
    old_state = (assoc) ? (assoc->cur_state):SCTP_STATE_CLOSED;\
    new_state = (g_sctp_fsm[old_state] + (pkg))->new_state;\
    new_assoc = assoc;\
    if ((g_sctp_fsm[old_state] + (pkg))->handler != NULL) {\
        new_assoc = (g_sctp_fsm[old_state] + (pkg))->handler((instance), (assoc), (sctp_parsed_info*)(parsed_info));\
    }\
    if (new_assoc) {\
        SCTP_TRANSFER_STATE(new_assoc,new_state);\
    }\
}while(0);