+/**
+ * @internal Calculate a sum of all words in the buffer.
+ * Helper routine for the rte_raw_cksum().
+ *
+ * @param buf
+ * Pointer to the buffer.
+ * @param len
+ * Length of the buffer.
+ * @param sum
+ * Initial value of the sum.
+ * @return
+ * sum += Sum of all words in the buffer.
+ */
+static inline uint32_t
+__rte_raw_cksum(const void *buf, size_t len, uint32_t sum)
+{
+ /* workaround gcc strict-aliasing warning */
+ uintptr_t ptr = (uintptr_t)buf;
+ typedef uint16_t __attribute__((__may_alias__)) u16_p;
+ const u16_p *u16 = (const u16_p *)ptr;
+
+ while (len >= (sizeof(*u16) * 4)) {
+ sum += u16[0];
+ sum += u16[1];
+ sum += u16[2];
+ sum += u16[3];
+ len -= sizeof(*u16) * 4;
+ u16 += 4;
+ }
+ while (len >= sizeof(*u16)) {
+ sum += *u16;
+ len -= sizeof(*u16);
+ u16 += 1;
+ }
+
+ /* if length is in odd bytes */
+ if (len == 1)
+ sum += *((const uint8_t *)u16);
+
+ return sum;
+}
+
+/**
+ * @internal Reduce a sum to the non-complemented checksum.
+ * Helper routine for the rte_raw_cksum().
+ *
+ * @param sum
+ * Value of the sum.
+ * @return
+ * The non-complemented checksum.
+ */
+static inline uint16_t
+__rte_raw_cksum_reduce(uint32_t sum)
+{
+ sum = ((sum & 0xffff0000) >> 16) + (sum & 0xffff);
+ sum = ((sum & 0xffff0000) >> 16) + (sum & 0xffff);
+ return (uint16_t)sum;
+}
+
+/**
+ * Process the non-complemented checksum of a buffer.
+ *
+ * @param buf
+ * Pointer to the buffer.
+ * @param len
+ * Length of the buffer.
+ * @return
+ * The non-complemented checksum.
+ */
+static inline uint16_t
+rte_raw_cksum(const void *buf, size_t len)
+{
+ uint32_t sum;
+
+ sum = __rte_raw_cksum(buf, len, 0);
+ return __rte_raw_cksum_reduce(sum);
+}
+
+/**
+ * Compute the raw (non complemented) checksum of a packet.
+ *
+ * @param m
+ * The pointer to the mbuf.
+ * @param off
+ * The offset in bytes to start the checksum.
+ * @param len
+ * The length in bytes of the data to checksum.
+ * @param cksum
+ * A pointer to the checksum, filled on success.
+ * @return
+ * 0 on success, -1 on error (bad length or offset).
+ */
+static inline int
+rte_raw_cksum_mbuf(const struct rte_mbuf *m, uint32_t off, uint32_t len,
+ uint16_t *cksum)
+{
+ const struct rte_mbuf *seg;
+ const char *buf;
+ uint32_t sum, tmp;
+ uint32_t seglen, done;
+
+ /* easy case: all data in the first segment */
+ if (off + len <= rte_pktmbuf_data_len(m)) {
+ *cksum = rte_raw_cksum(rte_pktmbuf_mtod_offset(m,
+ const char *, off), len);
+ return 0;
+ }
+
+ if (unlikely(off + len > rte_pktmbuf_pkt_len(m)))
+ return -1; /* invalid params, return a dummy value */
+
+ /* else browse the segment to find offset */
+ seglen = 0;
+ for (seg = m; seg != NULL; seg = seg->next) {
+ seglen = rte_pktmbuf_data_len(seg);
+ if (off < seglen)
+ break;
+ off -= seglen;
+ }
+ seglen -= off;
+ buf = rte_pktmbuf_mtod_offset(seg, const char *, off);
+ if (seglen >= len) {
+ /* all in one segment */
+ *cksum = rte_raw_cksum(buf, len);
+ return 0;
+ }
+
+ /* hard case: process checksum of several segments */
+ sum = 0;
+ done = 0;
+ for (;;) {
+ tmp = __rte_raw_cksum(buf, seglen, 0);
+ if (done & 1)
+ tmp = rte_bswap16(tmp);
+ sum += tmp;
+ done += seglen;
+ if (done == len)
+ break;
+ seg = seg->next;
+ buf = rte_pktmbuf_mtod(seg, const char *);
+ seglen = rte_pktmbuf_data_len(seg);
+ if (seglen > len - done)
+ seglen = len - done;
+ }
+
+ *cksum = __rte_raw_cksum_reduce(sum);
+ return 0;
+}
+
+/**
+ * Process the IPv4 checksum of an IPv4 header.
+ *
+ * The checksum field must be set to 0 by the caller.
+ *
+ * @param ipv4_hdr
+ * The pointer to the contiguous IPv4 header.
+ * @return
+ * The complemented checksum to set in the IP packet.
+ */
+static inline uint16_t
+rte_ipv4_cksum(const struct ipv4_hdr *ipv4_hdr)
+{
+ uint16_t cksum;
+ cksum = rte_raw_cksum(ipv4_hdr, sizeof(struct ipv4_hdr));
+ return (cksum == 0xffff) ? cksum : ~cksum;
+}
+
+/**
+ * Process the pseudo-header checksum of an IPv4 header.
+ *
+ * The checksum field must be set to 0 by the caller.
+ *
+ * Depending on the ol_flags, the pseudo-header checksum expected by the
+ * drivers is not the same. For instance, when TSO is enabled, the IP
+ * payload length must not be included in the packet.
+ *
+ * When ol_flags is 0, it computes the standard pseudo-header checksum.
+ *
+ * @param ipv4_hdr
+ * The pointer to the contiguous IPv4 header.
+ * @param ol_flags
+ * The ol_flags of the associated mbuf.
+ * @return
+ * The non-complemented checksum to set in the L4 header.
+ */
+static inline uint16_t
+rte_ipv4_phdr_cksum(const struct ipv4_hdr *ipv4_hdr, uint64_t ol_flags)
+{
+ struct ipv4_psd_header {
+ uint32_t src_addr; /* IP address of source host. */
+ uint32_t dst_addr; /* IP address of destination host. */
+ uint8_t zero; /* zero. */
+ uint8_t proto; /* L4 protocol type. */
+ uint16_t len; /* L4 length. */
+ } psd_hdr;
+
+ psd_hdr.src_addr = ipv4_hdr->src_addr;
+ psd_hdr.dst_addr = ipv4_hdr->dst_addr;
+ psd_hdr.zero = 0;
+ psd_hdr.proto = ipv4_hdr->next_proto_id;
+ if (ol_flags & PKT_TX_TCP_SEG) {
+ psd_hdr.len = 0;
+ } else {
+ psd_hdr.len = rte_cpu_to_be_16(
+ (uint16_t)(rte_be_to_cpu_16(ipv4_hdr->total_length)
+ - sizeof(struct ipv4_hdr)));
+ }
+ return rte_raw_cksum(&psd_hdr, sizeof(psd_hdr));
+}
+
+/**
+ * Process the IPv4 UDP or TCP checksum.
+ *
+ * The IPv4 header should not contains options. The IP and layer 4
+ * checksum must be set to 0 in the packet by the caller.
+ *
+ * @param ipv4_hdr
+ * The pointer to the contiguous IPv4 header.
+ * @param l4_hdr
+ * The pointer to the beginning of the L4 header.
+ * @return
+ * The complemented checksum to set in the IP packet.
+ */
+static inline uint16_t
+rte_ipv4_udptcp_cksum(const struct ipv4_hdr *ipv4_hdr, const void *l4_hdr)
+{
+ uint32_t cksum;
+ uint32_t l4_len;
+
+ l4_len = rte_be_to_cpu_16(ipv4_hdr->total_length) -
+ sizeof(struct ipv4_hdr);
+
+ cksum = rte_raw_cksum(l4_hdr, l4_len);
+ cksum += rte_ipv4_phdr_cksum(ipv4_hdr, 0);
+
+ cksum = ((cksum & 0xffff0000) >> 16) + (cksum & 0xffff);
+ cksum = (~cksum) & 0xffff;
+ if (cksum == 0)
+ cksum = 0xffff;
+
+ return cksum;
+}
+