lwip嵌入式的web服务器的外文翻译.docVIP

2011 届毕业设计外文翻译 毕业设计题目 基于LWIP的嵌入式WEB服务器的设计与实现 外文翻译题目 Design and Implementtation of The LWIP TCP/IP Stack 专业 通信工程 班级 姓名 学号 指导教师 职称 评分 指标 翻译工作量 1．饱满 2．较饱满 3．一般 4．较差 译文质量 1．好 2．较好 3．一般 4．较差 指导教师意见 签名： 得分： 日期： 评阅教师意见 签名： 得分： 日期： Design and Implementation of the lwIP TCP/IP Stack Swedish Institute of Computer Science February 20, 2001 Adam Dunkels adam@sics.se 1 API reference 1.1 Data types There are two data types that are used for the lwIP API. These are netbuf, the network buffer abstraction, and netconn, the abstraction of a network connection. Each data type is repressented as a pointer to a C struct. Knowledge of the internal structure ofthe struct should not be used in application programs. Instead, the API provides functions formodifying and extracting necessary fields. 1.1.1 Netbufs Netbufs are buffers that are used for sending and receiving data. Internally, a netbuf is associatedwith a pbuf as presented in Section 6.1. Netbufs can, just as pbufs, accomodate both allocatedmemory and referenced memory. Allocated memory is RAM that is explicitly allocated for holdingnetwork data, whereas referenced memory might be either application managed RAM or externalROM. Referenced memory is useful for sending data that is not modiˉed, such as static web pagesor images. The data in a netbuf can be fragmented into differenly sized blocks. This means that anapplication must be prepared to accept fragmented data. Internally, a netbuf has a pointer to one of the fragments in the netbuf. Two functions, netbuf_next() and netbuf_first() are used to manipulate this pointer. Netbufs that have been received from the network also contain the IP address and port num